Abstract: System factors play an important role in affecting the productivity of agricultural key factors during the process of agricultural development.The form of its expression is through industrial environment and technological efficiency to effect the change of agricultural output value.It was estimated by mathematical model that the share of system factors on the productivity of key agricultural factors was 40.97% during 1952 to 1992.Then based on this assumption it was suggested that improving system factors be the base for sustainable agricultural development in China.