Forty-three maize inbred lines in different heterosis groups were used to analyze the difference on grain filling and dehydration rate, in order to provide insights in breeding for maize varieties with high grain filling and dehydration rate. The results showed that: (1) the average yield of maize inbred lines was 4504.29 kg hm-2, while Jing724 showed the highest yield performance (7140.60 kg hm-2). The performance among different heterosis groups was revealed (X group > Reid group > Improved Reid > Huangzaosi improved lines > Reid group > Iodent group > P group> Lüda red cob group). (2) The average grain filling rate was 0.68 g-100 grain d-1. Jing2416 showed the highest grain filling rate (0.88 g-100 grain d-1), representing 0.28 and 0.19 g-100 grain d-1 higher than Zheng58 and PH4CV. Among different heterosis groups, X group was observed to higher than hat of Reid group, followed by Iodent group, Huangzaosi improved lines, Improved Reid, Lüda red cob and P group. (3) The average grain moisture content at harvest was 22.44%, and that of Jing2416 was 18.91%, which was 6.34% and 3.18% lower than that of Zheng58 (25.25%) and PH6WC (22.09%); the average grain dehydration rate after physiological maturity was 0.65% d-1, among which Jing2416 was the highest (0.82% d-1), 78.26% and 17.14% higher than that of Zheng58 (0.46% d-1) and PH6WC (0.70% d-1). The dehydration rate of different types of maize inbred lines was as follows: X group and Iodent group>Huangzaosi improved lines>Reid group>Improved Reid>Lüda red cob>P group. (4) Four inbred lines including Jing2416, JingB547, JingMC01 and Jing72464 showed higher grain filling rate and dehydration rate. (5) The grain yield was significantly positively correlated with grain filling rate and dry matter transport rate. A significant negative correlation between grain moisture content at harvest and grain dehydration rate after physiological maturity was detected, whereas a significant positive correlation between grain dehydration rate and grain filling rate after physiological maturity was observed. The results showed that the grain filling and dehydration rates of X group were higher than those of other genetic groups; Jing2416, the Huangzaosi improved lines, had the earliest maturity and the highest grain filling and dehydration rates, which had important breeding value for breeding new maize varieties with early maturity and suitable grain yield