Abstract: According to the time series of the total grain output in China, the paper resolves the totalgrain output into steady increasing trend output, meteorological fluctuation output and random output , and forecasts the total grain output in China up to 2000. Through analyzing the reason of fluctuation and its amplitude width with Delphi method and the interpretation of the structure model (ISM) , the structure model of the effecting factor of the grain problem has set up. The last part of the paper, three concrete countermeasures are presented.