After the purchase and sales of foodstuff in the main selling area of China being put into the market,Yandu County of Jiansu Province begins to develop the ordering foodstuff actively,hich achieves the satisfactory results on the efficiency improving of agriculture and the income increasing of farmers.

The article analyses China s grain comprehensive production capacity by using data of China s grain production from 1983 to 2005 and selecting the two major indicators of grain acreage and grain yield.

Taking 40 prefectural cities as assessment unit and using mathematical statistics indicators and geography information system,the paper presents comprehensive analysis on regional variations of grain yield of per hectare in northeast China in 2004,with three viewpoints of grain yield per hectare,annual growth rate from 1997 to 2004 and main crops yield per hectare.

Northeast China is a commodity grain base with strategic role in China,so researches on the change of grain yield per hectare in northeast China is of significance for ensuring China s grain security.

In this paper, the connotations of the risk of grain yield per hectare are explored and a new method is proposed to measure the risk of grain yield per hectare in Fujian province.

Change of drought condition in different economic regions and its relationship with fluctuation of grain yield per unit area;

Grain yield per unit area increased continually during the past near 50 years in HuangHuai -hai plain,and its increasing speed in recent years still kept higher than the average of all the country.

The variation trend of grain yield per unit area was studied with Yield channel in Liaoning province from 1949 to 2005,and the chemical fertilizer application and variation of fertilizer application structure from 1980 to 2005 were also studied.