To further promote the separation of government authorities，management and assessment is an important approach to facilitate reform and improve quality of higher education. This article which is based on Burton Clark’s analytical framework of triangle coordinated mode of higher education analyzes the internal and external factors of the separation of government authorities，management and assessment. Then it demonstrates according to the characteristics of higher education，the reasons behind the separation from the following dimensions：political power，bureaucratic hierarchy，academic authority and market force. Based on the demonstration，the article points out the basic mentality for the separation，which is the decentralization of administrative power，the reinforcement of academic authority and the exploitation of market force. At last，the article puts forward suggestions for the reform.