Abstract: We adopted 2D - saturation optimum design to determine the effects of density and row spacing on the yield of‘Wanmai 68’, and obtained comprehensive effect equation. The results showed that the density has a positive effect on yield, but the effect of the spacing was opposite. The interactions of 2 factors were negative. The density and spacing were positive for spike number, but negative for kernels per spike, and had less effect on the thousand kernel weight. The peak production of‘Wanmai 68’reached 9215.6 kg/hm², while the density was 3.5745 million/hm², and the spacing was 19.03 cm. The optimal yield components were 6.2448 million for spike number, 40.05 for kernels per spike, and 39.13 g for the thousand kernel weight. Synthesizing the extremum interval, the authors determined the seeding density of‘Wanmai 68’in Huaibei Region was 3.266-3.603 million/hm², spacing was 19-20 cm, and the production was more than 9000 kg/hm².