Abstract: This paper considers city planning as an institution and discusses several concepts when using contract analysis to study city planning. This paper combs the characteristics of contemporary contract analysis methods and points out the difference among contract analysis methods, legal contracts, social contracts, and contract doctrine. Combined with the characteristics of city planning, this paper proposes the concept of unfinished contracts, which is different from incomplete contracts of transaction cost economics. The paper also points out the necessity of using game theory tools for multi stage equilibrium analysis in the contract analysis of city planning.