This paper firstly gives the calculation of the productive public capital stock of 31 provinces during 1990-2005.Through the research of contribution elasticity of public disbursement to the economy,it found that: the unproductive public disbursement and the economical growth have the inverse correlation relations,on the contrary,the public capital is actually advantageous to the provincial capital area economy growth.The empirical research results for convergence of interprovincial economic growth model indicate neoclassical growth convergence trend by containing the common disbursement variable since 1990's.The conclusion draws lessons for common disbursement of government increment scale and structural optimization.Finally it gives the policy suggestion on changing public expenditure in provinces at present,which will also be the effective measure to reduce regional economies gap.