Abstract: This test aims to study main agronomic characters performance of corn in different planting densities. The authors chose‘XY696’and‘Tongli 11’as materials, to find the optimal coupling of planting density and corn varieties, develop high-yield cultivation techniques, and provide a theoretical basis for corn cultivation. The authors used two-factor randomized block design with different densities and varieties, set ‘XY696’and‘Tongli 11’as main treatment and density as deputy treatment. The test density was set as 60000, 70000, 80000, 90000 and 100000 per hm2, to determine the optimal coupling of the two varieties and planting density. The results showed that under low density, due to large plant nutrient area and good air and light conditions, the plant photosynthetic rate was high; under high density, due to small plant nutrition area and poor ventilation and light conditions, the plant photosynthetic rate was low; the planting density of the two varieties was in the range of 60000-90000 per hm2, the agronomic yield index was positively correlated with density, when the density was 100000 per hm2, the agronomic yield index showed a downward trend. Therefore, the optimal coupling of the two corn varieties and planting density was 80000 to 90000 per hm2.