On the basis of previous research results on potential agricultural productivity

the potential grain productivity of China is studied in this paper with the support of geographic information system （GIS） and national agricultural data\|base including spatial databases and attribute databases. At frist

the concept and development of potential grain productivity are expounded

and the method of GIS based study on the potential grain productivity is discussed. Then

after stressed research on such factors of potential grain productivity as soil effective coefficient

potential land productivity

social effective coefficient

and potential social productivity

the authors put forward some new computing models. Furthermore

using the mechanism methodology and computing models mentioned above

they calculated computed China’s national potential grain productivity by county unit. Finally

the predominance of exploiting potential grain productivity regions of China is determined through comparing the computing results with current grain productivity.