Grey incidence analysis between crop and its affecting aactors in Shandong Province

According to the statistical data during the last 50 years in Shandong Province, factors affecting grain production are analyzed by theory of grey system. The results are: (1)Total grain yield and grain yield per unit area showed a fluctuant increasing tendency since 1949;(2)Grain yield per unit is the most important factor that affect total grain yield; (3)Natural disasters in agriculture, multiple crop index and effective irrigated area cause the variation of grain yield remarkably. The author consider that relying on the advance of science and technology, strengthening construction of water conservancy works, developing technique of economize on water and improving low yield cropland are the key measures to realize the sustainable development of grain production in Shandong.