The purpose of this study is to review and to investigate the impact of psychological contract on organizational commitment and the mediating role of justice perception and trust. In addition to those relationship the differential impacts of transactional contract and relational contract on continuance commitment and affective commitment are examined respectively. Critical review of the previous studies reveals that transactional contract has positive impact on continuance commitment and justice perception mediates the relationship between the two constructs, and relational contract has positive impact on affective commitment and trust mediates the relationship between the two constructs. The results from the empirical study with 201 samples of hotel employees in Seoul shows that 1) transactional contract has positive impact on continuance commitment but justice perception does not mediate the relationship between the two constructs, 2) relational contract has positive impact on affective commitment and trust mediates the relationship between the two constructs.