Based on the panel data of 17 important grain-production provinces in China from 1992 to 2014, the paper makes an empirical analysis of the influence of various factors on the grain yield. The research finds that: a) Seeding area is the deepest influence factor on grain production; b) Labor transfer has not affected grain yield at the present stage; c) Technical progress has the most obvious and most potential impact on the increase of grain production; d) The affected area is obviously not conducive to grain production, and e) Fiscal expenditures for supporting agriculture can improve grain production, but the effect is relatively weak. By comparative study of wheat and rice, the above conclusions still stand up. But there exist significant differences in the regression results of the two staple varieties, namely， wheat yield is more sensitive to the farmland area, the use of fertilizer, meteorological disasters, and fiscal expenditure for agriculture, while the rice yield is more sensitive to labor input.