Dongchangfu County is a county with the characteristics of Liaocheng and agriculture area of north china and Huanghuaihai region. It has large population and less developed economic, particularly rural economic is backward. With the development of 50 years in the past it had formed four characteristics of PRED system. Firstly, gross population is large scale and increasing rapidly, but less educated. Secondly, natural resources such as mineral, water and energy are scare, land resources are main natural resources but are poor and less productive. Thirdly, natural disasters such as drought, flood, saltization and alkalization had been better prevented from, but some of them still did great damages to people; fourthly, with the rapid growth of economic, capital and technology inputs are less sufficient, it consumes large resources with large waste.\;The study on motive forces of sustainable rural economics is the research of main promoting forces and the restricted factors which hamper the economics growth during the year of 1980 to 1996, when the development of it was the fastest in the past, the aim of it is to foster the growth pole of sustainable rural economic and take the measures to it correspondingly.