With the increasement of the city vehicles, the problems of traffic accidents, traffic offense and congestion in city become more and more serious. However, the number of the traffic police is limited, so the former ways of working, such as traffic patrol and working at regular places, cannot effectively solve the problems above any more. Through the analysis of the large working scale and mobility characteristic of the traffic police working, the research designed and realized the mobile office system, which could effectively learn the traffic jam situation and solve the jam problem. The system can also effectively collect the information of the traffics, deal with the traffic accidents and traffic offense which could greatly improve the work efficiency of the traffic police.