The regional growth as the background, this paper discusses the role of government expenditures equilibrium path In developed region and undeveloped region model, this paper discusses the financial expenditure marginal contribution rate and regional financial expenditure structure’s effect on regional economic development and the regional economic differences, calculates the optimal financial expenditure scale of the developed areas whose financial expenditures usually exceed the optimal spending scale It is necessary to implement the lateral transfer payment, narrow the gap between the areas At last, the policy implications are analyzed