The development of a dynamic game model for planning a double and duplication of supervision based on the indeterminate appointment probability and order of supervisors on the grounds of the current causes of planning and supervision collusion in real estate land is presented in this paper and the question how to separate the planning from supervision availably is analyzed. The dynamic game is employed for the study. Results are as follows: First, feasibility and availability of planning a double (planning and supervision) are verified theoretically, which can reduce the monitoring cost. The higher the appointment probability of the second party of planning supervisors, the greater the risk pressure and moral remorse of the earlier planning supervisors. Thus, milder punishment is required to separate planning from supervision. Secondly, under planning and supervision, the earlier planning supervisors always dread supervision from the second party and the collusion probability with real estate developers is reduced. Therefore, the policy of planning and supervision should be vigorously marketed.