Abstract: Abstract: Sustained and stable growth of grain production is very important for national food security in China. As one of the most important production bases and commodity grain bases in China, Huang-Huai-Hai Region plays an important role in ensuring national grain security. It is of positive significance to enhance food production by decomposing the impact of each factor on grain production and identifying the dominant factors. Taking 347 counties as sampling units in Huang-Huai-Hai region, and adopting the logarithmic mean weight divisive method (LMDI), the grain production was decomposed into four effects, i.e., cultivated land area, multiple cropping index, grain farming index, and grain yield per hectare. On the basis of the LMDI model, effect and accumulated effect of each factor were explored.First, the grain production increased by 1.01 ×108 t from 1980 to 2010 in Huang-Huai-Hai Region, accounting for nearly 45% of the increased grain yield in China, and the pattern "high in the southern while low in the northern and central" of grain yield is very evident. The counties with higher grain yield are gathered in North Jiangsu, North Anhui, Eastern Henan, and Western Shandong. Secondly, the accumulated effects of cultivated land area, multiple cropping index, grain farming index, and grain yield per hectare are 57×104 t, 1457×104 t, -991×104 t, and 9 626×104 t, respectively. Among the four factors, grain yield per hectare was confirmed as the dominant contributor to the growth in grain production, and the increase of grain production by the effect of grain yield per hectare was more than 45.0×104 in most of counties in North Jiangsu, North Anhui, Eastern Henan, and Western Shandong; the multiple cropping index was the second important contributor to the growth in grain production, and the positive accumulated effect of multiple cropping index was more obvious in North Anhui, Eastern Henan, and Western Shandong. The grain farming index played an important role in the decline in grain production, and the accumulated effects of the grain farming index in 233 counties were negative. The accumulated effect of the cultivated land area was non-significant, but with obviously spatial difference, and the negative effect was more obvious in counties with a superior location and an abundant economic basis. Thirdly, there are obvious differences among the four factor effects at the county level in the Huang-Huai-Hai region. Overall, multiple cropping index and grain yield per hectare prompted a significant increase of grain production in northern Jiangsu, northern Anhui, and eastern Henan; superposition of the grain farming index, multiple cropping index, and grain yield per hectare showed a significant increase of total grain production in western Shandong.In view of the spatio-temporal variation of grain production and regional difference of the four factors, some work such as technological progress, cultivated land balance, and the optimization of regional planting structure should be enhanced to maintain the growth trend of grain production in the Huang-Huai-Hai region.