Abstract: In drder to construct a suitable maize population structure and achieve high yield and stress resistance cultivation of maize, in this experiment, Nendan 22 was used as the test material, and four planting density levels were set, which were 6.00×10~4 plants·ha^-1（M1）,6.75×10~4 plants·ha^-1（M2）,7.50×10~4plants·ha^-1（M3） and 8.25×10~4 plants·ha^-1（M4） were sprayed with chemical regulator Yuduoshi（HK） and clear water control（CK） at the 8th leaf expansion stage. The results showed that with the increase of planting density, the plant height and spike height increased significantly, the internode length of stem became longer, the stem diameter became smaller, the flattening rate increased, and the stem strength became weaker. After HK treatment, plant height and spike height decreased significantly, internode length at 4-5 nodes decreased, stem diameter increased, flattening rate decreased, and stem strength increased. After chemical control treatment, the transverse bending strength and puncture strength of the stem increased, with the largest increase in the 4-5 nodes of the stem. The lodging rate increased with the increase of planting density, and the lodging rate could be significantly reduced by chemical control treatment, which decreased by 34.62%, 43.81%, 37.26% and 30.82% respectively compared with the control under four planting densities.