Abstract: Regular sowing date (October 10) and moderate late sowing date (October 20) were designed in this study using a large-spike winter wheat variety‘( Tainong 18’) as the experimental material. Furthermore, on each sowing date, three planting densities were designed at 2.25, 3.75 and 5.25 million plants/hm2 respectively. The interactive effects of sowing date and planting density and their interactions on the grain yield, culm height at the center of gravity (CHCG), culm mechanical strength of the second base internode (CMS) and the culm lodging resistance index (CLRI) of winter wheat were studied to clarify the regulation of late sowing on grain yield and culm lodging resistance of high-yield winter wheat. The results showed that the interactive effect of sowing date and planting density significantly influenced the yield and lodging resistance of winter wheat. Properly increasing planting density to 3.75 million plants/hm2 could achieve high yield by improving the number of spikes during each sowing period, and there was no significant difference between the two sowing dates. Moderate late sowing increased the CLRI of the winter wheat enormously in various planting densities. Under the late sowing condition, with the increase of planting density, the improvement of the CHCG and the reduction of the CMS were obviously lower than those of the conventional sowing date. Therefore, the CLRI of winter wheat at relatively high density could still be maintained at a high level. The winter wheat planted at a relatively high density could balance its high grain yield and high lodging resistance by means of sowing relatively late. In this research, the high yield and the stable production could be achieved simultaneously when sowing on October 20 at the planting density of 3.75 million plants/hm2.