This study is aimed at these research gaps in the regulatory focus theory, developing and testing a research model in Taiwan's National Police Agency setting, which investigates the relationship among transformational leadership, regulatory focus, uncertainty towards organizational change, and organizational commitment. The subjects of this study are 860 full-time employees in National Police Agency of Taiwan. Structural Equation Modeling was used to test this study model. These results are that transformational leadership has a significant positively influence on promotion focus or organizational commitment, the role of promotion focus plays a mediator in the relationship between transformational leadership and affective commitment. In addition, promotion focus has a significant positively influence on uncertainty towards organizational change and affective commitment. Further, prevention focus is positively related to uncertainty towards organizational change and normative commitment. Uncertainty towards organizational change is negatively related to organizational commitment. Implications, limitations and directions of future research are discussed.