Summer corn varieties Beinong5, Fudan2, Fengyu8, Dafeng28, Xinzhongyu801, Fudan4 and Sanbei89 were used as tested materials, dry matter accumulation, grain filling rate and grain dehydration rate were determined. Investigation on mechanized harvesting characteristics during harvest period and the varieties of machine harvested grains were screened. The results showed that the dominant period of dry matter accumulation of maize varieties Fudan2 and Bainong5 with high yield was medium and late. The accumulations of individual plants of early maturing variety Fengyu8 and Dafeng28 were 282 g and 285 g, respectively, which were far lower than those of medium late maturing varieties. The grain filling rate of maize was basically the same, reaching a peak at about 15 d after pollination, then gradually decreasing. The water content of grain was higher than 27%, the crushing rate of corn groats was less than 1%, but the loss rate of the grain harvest was less than 5%, and the qualified rate of the cut length of the straw was higher than 93%, which was in line with the standard. Combining the harvesting characteristics of all varieties, the yield of Fudan2 and Bainong5 are 6 432 kg/hm2 and 6 342 kg/hm2 respectively. The grain loss rate is low and the stalk is tough and resistant to fall, which basically meets the requirement of the grain harvesting, and it is suitable for the cultivation of the harvested varieties in Dongting Lake area.