Amid the transformation of operating environmental conditions and the changes in market, a business organization must think how to construct flexible manpower in order to respond to the changes in industries and markets. The traditional organization of hierarchy, which lacks flexibility, doesn¡¦t induce the flexible use of manpower and thus is ineffective in meeting the trends of industries and the market. Atkinson advocates demolishing the rigid system and, based on the characteristics of business production activities, dividing the organization into the core and periphery manpower so that the two sections can be complementary and each possible combination of manpower can be optimal. However, there exists the combination of three types of manpower in the shamrock organization mentioned by Handy, namely, professional core worker, temporary worker, and subcontract worker. The professional core worker can be compared to the core manpower mentioned by Atkinson, and the temporary and subcontract worker correspond to Atkinson¡¦s periphery manpower. The combination of these three types of manpower can be used to produce the foundation of the business¡¦ profitability. In addition, the current human resource arrangement should be adjusted in order to respond to the changes in the market in a timely manner. It is available to implement task flexibility, numerical flexibility, working-time flexibility, and wage flexibility to meet the practical work demands. This research based itself on the preceding concept, conducted interviews with China Steel Corporation and its subcontractors, and collected data through survey questionnaires administered to the subcontractors. The survey was conducted to understand how China Steel Corporation and its subcontractors divided their core and periphery manpower, how they constructed the shamrock organization, and how they used their manpower flexibility. The research also investigated whether there existed differences between China Steel Corporation and its subcontractors with regard to manpower flexibility. The analysis and synthesis of the data have led to the following findings: China Steel Corporation (CSC): 1.China Steel Corporation adopted for its main production line the shift system and mutual support of manpower to meet the requirements of the changing market and job demands, while the engineering and the equipment department adopted subcontracting to meet the change in the demand of manpower. 2.China Steel Corporation did not use temporary workers, but its subcontractors employed a large number of temporary and subcontract workers. As a result, the workers of China Steel Corporation and the temporary and subcontract workers of its subcontractors operate together at CSC, like the operation of a shamrock organization. 3.Without the worry of impeding quality, quantity, and safety, the job at the technical level was divided into core and non-core, with the core job emphasizing the creation of additional value. 4.The non-core job was carried out by the periphery workers, who consisted of the employees of subcontractors specialized in operation, construction and environmental protection and of other contractors. 5.China Steel Corporation enhanced the use of task flexibility through the use of task grouping, task changing, and job rotation, and expanded the scope of task flexibility through transferring and assigning personnel to auxiliary companies. At the same time, education and training were implemented to support the use of task flexibility. 6.With respect to the use of numerical flexibility, China Steel Corporation adopted subcontracting as the major measure of response. 7.With respect to the use of time flexibility, China Steel Corporation adopted such systems as flexible reporting and leaving time, shift, overtime, and optional leave instead of overtime pay. 8.As to the use of wage flexibility, China Steel Corporation raised the percentage of mobile wage, added wage flexibility, and used the bonus system to reflect the merits of the company and individual employees. Subcontractors: 1.Faced with the changes in the market and job requirements, they used temporary and subcontract workers as the major measure of response. Dependent on networks of interpersonal relationships, they hired temporary workers and provided support to subcontractors so that they tied closely into a shamrock organization. 2.About 30% of the CSC¡¦s subcontractors cultivated their employees to become their own subcontractors. The success of this plan depended on the limiting conditions for fund investment, the vitality of the industry, and the support made available by the CSC¡¦s subcontractors. 3.Monetary compensation was the major factor of retaining the core manpower, and the promotion system accounted for only 29.4% of manpower retention, which was related to the flat organizational structure. 4.More than half of the CSC¡¦s subcontractors assigned additional work, work requiring less training, and unimportant work to temporary workers. More then 60% of CSC¡¦s subcontractors would complete work requiring special skills or equipment through subcontracting. 5.With respect to the use of task flexibility, 70.2% of the CSC¡¦s subcontractors that implemented task flexibility experienced such a difficult situation in which a new hand was unable to handle his work. Only 32.7% of the subcontractors would give relevant training in advance, indicating that education and training did not support the use of task flexibility. 6.With respect to the use of numerical flexibility, 69% of the subcontractors hired temporary employees, and 62% of them used subcontracting. 7.With respect to the use of working-time flexibility, most CSC¡¦s subcontractors used overtime, shift, and varied time block as the major measure, for they had to coordinate operation with CSC and could not be independent in terms of working time. 8.With respect to the use of wage flexibility, the percentage of wage base linked to merit was low, and skills were more important than merit in deciding the wage of a temporary worker. 9.There existed no significant differences in wage and promotion between the core and periphery workers of the CSC¡¦s subcontractors. 10.There existed differences in benefits and training between the core and periphery workers of the CSC¡¦s subcontractors. Differences in the Use of Manpower Flexibility Between China Steel Corporation and Its Subcontractors: 1.China Steel Corporation had a high percentage (64%) of core workers and a relatively low percentage (36%) of periphery workers. In contrast, its subcontractors had a high percentage of periphery workers (including 34% subcontracting and 28% temporary workers, totaling 62%) and a low percentage (38%) of core workers. 2.As to the difference in task flexibility, China Steel Corporation had subsidiary companies and could expand the scope of task flexibility. In contrast, their subcontractors had no subsidiary companies and their task flexibility was restricted to the same enterprise. In comparison, China Steel Corporation invested more in education and training and was more competent in supporting task flexibility. 3.With respect to the difference in numerical flexibility, China Steel Corporation cared about the legality of using temporary workers while its subcontractors neglected this issue more or less and was less bound by labor unions with regard to using temporary workers or subcontracting. In practice, the CSC¡¦s subcontractors had more numerical flexibility than China Steel Corporation. 4.With respect to the difference in working-time flexibility, China Steel Corporation abided by the regulations regarding working overtime while its subcontractors did not pay attention to these restrictions. 5.With respect to the difference in wage flexibility, the wage structure at China Steel Corporation is institutionalized, about 30% belonged to mobile wage and was linked to the company¡¦s operation and individual employees¡¦ merit. On the contrary, the questionnaire survey collected from its subcontractors indicated that only a few of them assessed the wage base on merit.