This study discusses an activity competency model (ACM) which was utilized to investigate the perceived importance of managerial activities and skills/knowledge required of three management levels of Multi-national Corporation (MNC) under cross culture working environment in Middle Eastern area country. The 177 samples of this study collected mainly on different level of mangers from seven oil; petrochemical manufacturing industries and six service industries such as financial companies; bank and trade companies. Many quantitative methods, including factor analysis, one-way ANOVA, t-test, data correlation were utilized to test the hypothesis of this research. The major findings of this study are summarized as following: (1) the importance of MNC managerial activities varies significantly for both different levels of management and different industries. (2) the most important managerial three skills; communication, persuasiveness and coordination skill; planning and organizing skill; leadership skill are all identical in each management level and industry type as well. (3) it is very diversity in terms of cross-relationship between managerial skill and activity. (4) it is more concern on diversity of culture for lower management level than for upper level due to frequent personal contact and communication. The results of this study have implications for MNC management development, training, and management career planning. They can also serve as a guideline for recruiting or dispatching the capable expatriate manager for international business enterprise.