The effects of different planting densities on the particle size distribution and pasting properties of starch granules in maize grains along the Huaihe River were analyzed. Taking 13 maize hybrids such as Yudan 132 and Jingke 968 as materials, three planting densities of 56 250 plants/hm2, 67 500 plants/hm2 and 77 250 plants/hm2 were set up. The effects of different planting densities on grain quality, starch particle size distribution and gelatinization characteristics of maize in the region along the Huaihe River were analyzed. The results indicated that the protein and fat content of maize grain decreased with the increase of planting density in the range of 56 250 ~ 77 250 plants/hm2. The starch content showed an increasing trend, which means, the starch/protein ratio increased. The volume and surface area percentage of large starch granules in maize grains increased significantly, while the small starch granules decreased significantly. At the same time, it was found that the peak viscosity, trough viscosity, final viscosity and breakdown value of corn starch increased significantly after rising planting density. Relevant analysis showed that the viscosity parameters such as peak viscosity of corn kernels were positively correlated with the volume percentage of small and large starch granules. There was a significant or extremely significant negative correlation with the volume percentage of medium starch granules. It shows that planting density affects the starch particle size distribution starch viscosity parameters and chemical components of corn kernels.