| With the acceleration of our urbanization and industrialization and intensification of aging of population in rural areas, peasants'demands of rural pension insurance system have become more and more fierce. Both <Several Suggestions of CPC Central Committee and the State Council on Promoting the Construction of a New Socialist Countryside> and"the 11th 5- year plan"have regarded the establishment of rural social pension insurance system in accordance with the development level of rural economy and match with other guarantee measures as an important part in promoting the construction of a new socialist countryside and placed it at an outstanding position. This article sets rural pension insurance system as research object and aims to seek the factors influencing its demand and the optimal scale of institutional supply from our governments at various levels from the perspective of demand and supply of institution.The third chapter makes theoretical analysis on the demand of our rural pension insurance system from both macro and micro level and makes correlation and regression analysis on factors influencing peasants'enthusiasm in participating insurance in rural areas by introducing relative variables. The fourth chapter introduces the concept of transaction expense in institutional economics and tries to analysis the institutional supply of government at all levels by means of analyzing supply entity model of public goods after defining the attributes of public goods of rural social pension insurance systems.In this article, the author believes that the key factor influencing rural pension insurance systems is collective allowance; even a small sum of allowance can stimulate peasants'participation enthusiasm in insurance. And the key factor influencing instructional supply of governments at all levels is transaction expense. So governments should decide the optimal scale of their intuitional supply on the base of transaction expense. The fifth chapter makes an analysis on reasons of severe imbalance between supply and demand of rural pension insurance system and points out that the government should be responsible for the shortage of effective supply that causes the imbalance, which is in large part because of game between central government and local government in intuitional supply. In the last part, the author puts forward some suggestions on how to improve rural pension insurance system in China in reference of reasons elaborated from model and makes some prospects of what role should commercial insurance play in rural pension insurance system. |