Since the open door policy, the PRC’s social structure has been deteriorating and its social stratums have been broadening along with the economic development. Comparing to the long-standing social stability before the open door policy, the central CPC has worried about the deteriorating development of social order and crime problems triggered by the redistribution of wealth. The central CPC thought that the Ministry of Public Security could not handle the social order and crime problems with its old system and functions. The problems would have great negative impact on the CPC’s ability of internal control, if the police systems and functions had not been reformed or improved. This study has found that on the basis of the highest guideline of “one center and two basic points,” the progressive reform steps taken by the Ministry of Public Security were as follows. First, it aimed at the reform of police organs and administrative systems. Second, it focused on the reform of police assignments system. Third, it stressed on the reform of grass-roots police and stations. Lastly, it emphasized on the reform of the concept of law enforcement and the quality of the police. To sum up, there were four development shifts on police. The first one was the reform of police organs and administrative duties from 1979 to 1996. The second one was the reform of police assignments system form 1997 to 2002. The third one was the combination of crime control, prevention and crackdown by police stations and community policing from 2003 to 2005. The fourth one was the three-base project from 2006 to 2008. The new Minister, Meng Jen-tzu, took office at the end of 2008 and he addressed “the three-construction” project as the further and sequent fulfillment of the three-base project. The related developments of the three-construction project are still going on. How they shape the functions and roles of the Ministry of Public Security requires sequent observation.