In order to provide the basis for the breeding and improvement of density-tolerant varieties, the change characteristics of ear traits of maize hybrids and the response to planting density were studied, taking maize hybrids popularized in China from four different eras since the 1980s as the materials. From 2017 to 2018, 12 maize hybrids with a large planting area of popularization released from 1980s to 2010s were investigated in Shenyang, Liaoning province and Gongzhuling, Jilin Province, with the two planting densities of 60,000 plants hm_-2 and 120,000 plants hm_-2^, using split plot experiment design, four row plots and three replicates. Ear length, ear diameter, bald tip length, rows per ear, kernels per row, and 100-kernel weight were investigated after harvest. The maize varieties released from different eras showed extensively significant change for rows per ear, kernels per row and 100-kernel weight in the present study. Ear diameter, bald tip length and 100-kernel weight decreased under different planting densities with the decades, rows per ear showed the opposite trend, and ear length and kernels per row did not change significantly. The change of bald tip length was especially significant, with the average decrease of 0.24 cm (high planting density) and 0.19 cm (low planting density) every 10 years from 1980s to 2010s. With the increase of planting density, the ear length became shorter, ear thinner, bald tip longer and kernels per row reduced for maize hybrids in the same era. Among them, the decrease of the new varieties released since 2000s was smaller, and the increase of bald tip of the new varieties in 2010s was the least with the value of 1.04%, indicating that the new maize varieties were more tolerant to density. In the future, it is necessary to maintain higher 100-kernel weight, while strengthening the synergistic improvement of ear length, ear diameter and bald tip, so as to achieve the goal of increasing yield during the breeding of density-tolerant.