With Taiwan High Speed Rail Corporation as the study subject, this study investigated the effects of job status, role conflict and organizational commitment on organizational citizenship behavior in the BOT project. Questionnaires were used for data collection and hierarchical regression analyses were used to test the hypotheses. Data was collected from 343 employees in Taiwan High Speed Rail Corporation. It is found that standard workers have a higher level of organizational commitment than nonstandard workers. Role conflict is found to have a negative effect on employees' organizational commitment. It is also found that organizational commitment has a positive effect on employees' organizational citizenship behavior. Theoretical and practical implications of the results are discussed.