The way for the government to execute power has crucial influence on the boundary between government and society. When does the government choose Direct Management （DM） governance system？When does the government choose Assigning to the Society （AS） governance system？With the help of mathematical model，this paper attempts to reveal the logics inherent in the behavior of government. There is a fundamental trade-off faced by the government when making decisions：if it chooses DM governance system，although it can reap the invisible benefits resulting from the control of executive power，it should bear the political risks in the process of executing power；if it chooses AS governance system，while it can avert political risks，it also loses the opportunity to grab invisible benefits. This paper discusses the change of parameters and their influence on the choice of equilibrium governance system. This model can shed light on the understanding of logics behind the choice of governance system of the project —“Defining Land Property” in rural areas of Chengdu. This paper brings consumer complaint into analysis and study the role of “fire alarm” mechanism in affecting the choice of governance system decided by government.