In this study, two pairs of hybrids and their parental inbred lines of maize which planted in early-maturing and very early-maturing in Heilongjiang were used, Demeiya 2 (low moisture content) and Keyu 17 (high moisture content), Demeiya 3 (low moisture content) and Zhedan 37 (high moisture content), which were significant difference in grain moisture content at harvest. The dynamic changes of grain moisture content, dehydration rate, and filling rate were investigated to find the relationship with the moisture content of harvest. The results showed that the grain moisture content of Demeiya 2 and Demeiya 3 were significant higher than Keyu 17 and Zhedan 37 at harvest stage respectively. The grain moisture content of maize hybrids showed no significant difference in varieties until physiological maturity stage, then the difference gradually increased. The grain filling rate of two varieties with low moisture content (Demeiya 2 and Demeiya 3) were 0.12g/d quicker than other two hybrids with high moisture content (Keyu 17 and Zhedan 37). The difference was derived from female inbred lines. Three days difference from pollination to physiological maturity were detected between hybrids with low and high grain moisture content at harvest, which were derived from the female inbred lines. The dehydration rate became quicker, which were detected in the male and female inbred lines. There were the extremely significant and significant negative correlation between the grain moisture content at harvest and the grain dehydration rate and the grain filling rate respectively. The results should be benefit for maize hybrid breeding and innovation of resource with low grain moisture content at harvest, quick dehydration and completely mechanized production.