The cost management and control are the important topic that most of enterprise operators have to confront with. Facing the increasing competition in enterprise environment, it is, in active respect, necessary to control the cost effectively in order to gain niche in keen market competition; in positive respect, it is to avoid any error policy decision because of inaccurate cost data. In traditional cost accounting, the allocation method of overhead is incomplete so that it is easier to result a distortion phenomenon in production cost structure. For the past years, the management academic world has proved through detailed study and real application that using the Activity-Based Costing (ABC) System can improve the defect of traditional cost accounting. The reasonable operation analysis and the exact cost driver allocation of ABC System will enhance the accuracy of the cost data. This case study company is a sole integrated steel producer in Taiwan. Due to the diversity of products, the company¡¦s production processes are extremely complicated and varied. The existing cost management system is unable to provide an actual cost under the different processes. Therefore, there is a room for improvement in analyzing the cost sharing of product expenses. This report takes the case study company¡¦s BOF plant as an example to research, by means of the process analysis, how to allocate the cost exactly, and to make a new cost system which can match the spirit of ABC. Meanwhile, this report makes a comparative analysis between the original cost system and ABC one. The result of the research revealed that the ABC cost system may truly improve the phenomenon of distortion of the product cost structure in the case study company. Using ABC cost system may not only promote the accuracy of the cost information, but also enhance the working performance under the activities analysis and control and reduce the waste of resources.

It is a critical issue for enterprises to manipulate the competitive strategy, cost control, and increase ability in the intensive competition. The major duty of cost management is how to offer data or information that are truly needed for their managers, and how to present data or information on time, reasonable, or correct. In order to understand the cost management is satisfaction to its management decision or not, and what is its really need on cost management of target enterprise. This research adopted interview method which were given to each level managers and also try to access related information to prove the really requirement of cost management. In this research, we computed the detailed product cost of target enterprise, and analyzed these figures under the basis of Standard Product Cost and actual cost. We found there were 474 categories included in this company of its norm of product item of F10 category. Furthermore, according to the cost data that showed on its financial report when we compared the cost of the detailed product norm, we found that the lowest was 92.92% below the average cost and the highest was 154.27% above the average cost. There is obvious difference between the lowest and the highest cost; therefore, as an information provider, he or she has the obligation to frankly express related data to managers and help them to make a correct decision. The case company currently applies Standard Product Cost system as its cost system. However, it is not alike traditional cost system, there are some similar with Activity Base Cost system. In this dissertation, we will modify or add some cost data and procedure of cost process under current cost system. After modification cost system, we attempted to calculate reasonable detailed product cost base on actual cost. Fortunately, when we combined the modification cost system and order system of the target enterprises, we discovered some results and those help us to realize cost information of customer and appraise the contribution of each sales order or every customer. To do so, we can provide the calculation of performance of product cost and exploitation efficiency of new product, before and after of quality improvement of each product. Finally, the modification cost system also can be used as reference for sales pricing and profit planning of combination production-sale system.