Abstract: In order to study the reason of the short husk variety in the process of maize inbred lines from microscopic perspective, the vascular bundle characteristic in the cob and the husk were measured by using different varieties of the maize, including the short husk variety of 139 and the contrast variety of No.1. The physiological studies on the ear development of maize showed: In the four period of ear growth the husk nitrate reductive activity of No.139 was very lower than that of No.1. the husk glutamine synthetase activity was lower than that of No.1, and the change of glutamine synthetase activity of No.1 was flat. The ear nitrate reductive activity of No.139 moved acutely, and after 15days pollination that of No.139 reached maximum that was higher obviously that of No.1 at the same period. The ear glutamine synthetase activity of No.139 always higher than that of No.1 in the the three period. In the last period ,the ear glutamine synthetase activity of two inbred lines were almost equal.