Some big cities are now facing a dilemma which one side there are lots of illegal parking on the road, on the other side the off-road parking lots are not used effectively, these are all due to the unreasonable parking policies. This paper has analyzed reasons for the game occurring in parking problem from three respects, and bring forward that the essence of parking policy is to adjust the objective factors influencing parking choice to equilibrate the parking lots used. From the game theory perspective, this paper analyzed the reasons that produce the problems of congest parking in on-street parking lots and insufficient of berths. Finally a concrete policy measures is given to enhance the efficiency of parking lots using and find a way out of illegal parking.