With the rapid development in China's IT outsourcing industry, the number of employees in software outsourcing enterprises increases rapidly. IT expatriates not only bring huge economic benefits to the software company, but also reduce the customers’ development and operation costs, improving IT performance. However, since these expatriates who are away from the parent company, are working in customer side for a long time, and do not belong to the client company either, they are always regarded as “third country citizens”. Thus, identity disorder and lack of organizational commitment to their parent companies are always haunting around them. This paper studies the influences of employees’ and enterprises’ psychological contract in different matching patterns on organizational commitment by empirical analysis method. This research finds that employees’ relational psychological contract has a higher positive influence on organizational commitment than employees’ transactional psychological contract in both matching and mismatching situation, while enterprises’ relational psychological contract only affects the organizational commitment more positively than the transactional psychological contract in a matching situation. The employees of mutual-loyalty pattern and employee-dominating pattern will have a stronger organizational commitment in matching and mismatching situation separately. This research develops the relevant theory of psychological contract and organizational commitment in the background of IT outsourcing, improving the staff management for IT outsourcing enterprises efficiently.