The problem of agriculture,countryside and peasant has become a social focus which has been paid close attention by the central government and various circles of society. Whether we can solve this problem successfully will directly influence the sustainable development of agriculture and the comprehensive progress of social economy. From the point of view that combine historic search and practical introspection organically, this article explores four contributing factors of this problem, which are the market, institution, national condition and policy. Thus this article provides a premise of basic theory for resolving the problem of agriculture, countryside and peasant effectively.