Abstract: In order to improve the planting technology level of Heyu 187 and give full play to the potential of increasing yield and income of cultivation measures,this study adopted a split plot experiment design.The main plot was the planting density,and three density levels were set,M1 was 52 500 plants·hm^-2,M2 was60 000 plants·hm^-2 and M3 was 75 000 plants·hm^-2.The secondary area was the nitrogen application level.Three nitrogen application rates were set,N0 was pure nitrogen 0 kg·hm^-2,N1 was pure nitrogen 150 kg·hm^-2,and N2 was pure nitrogen 300 kg·hm^-2,respectively.The effects of planting density and nitrogen application rate on the agronomic characters and yield of Heyu 187 were studied.The results showed that at the same density level,plant height,panicle position,panicle length,panicle diameter,number of rows per panicle,number of grains per row and 100-grain weight increased gradually with the increase of nitrogen application rate,while the empty stem rate and lodging rate also increased with the increase of nitrogen application rate.The maximum maize yield at N1 level was 5 916.2 kg·hm^-2,and there was no significant difference between N1 level and N2 level.Under the same fertilization level,with the increase of planting density,ear length,ear diameter,row number of ears,row number of grains and 100-kernel weight decreased,the maize yield under M1 level and M2 level were all significantly different,but not significantly different from that under M3 level.When maize was planted with low density,higher yield could not be obtained by increasing N application rate.When maize was planted with high density,insufficient nitrogen application would lead to malnutrition of maize population,which would affect dry matter accumulation of maize grains and decrease maize yield.The ideal yield can only be obtained by adjusting the nitrogen application and planting density reasonably.