Abstract: In this study，five maize varieties，Longping 206，Huawan 267，Yudan 112，Qiyu 606，and Luyu 4130，were selected as materials for the top ear position and middle ear position grains to study the difference in grain vigor of different ear positions. The germination index，100-kernel weight，and simple vitality index of seed were analyzed to explore the relationship between different ear positions of maize and seed vigor，and a basis for selecting maize seeds with optimal ear positions and high vigor was provided. The results showed that the germination vigor and germination rate of the five varieties were all higher in the middle part than the top part，and there was no significant difference in the germination rate among different positions of the same variety. The seedling height and root length of the five varieties were all greater in the middle part than the top part，and the fresh weight above the ground and the fresh weight in the ground was also greater in the middle part than the top part in the two repetitions of the five varieties. For the five varieties，the simple vitality index of the middle grains on the simple vitality index I，the simple vitality index II，and the simple vitality index III was greater than the simple vitality index of the top grains. The vigor index was different between different varieties，and the vigor index between different ear positions of the same variety was also different. In the two ear position treatments，the vigor of the middle grain of maize was greater than that of the upper part，and there was a positive correlation between the grain vigor and 100-kernel weight of the grain.

Key words: ear position of maize, germination vigor, germination rate, vitality index