To explore the effects of sowing date and density on grain yield of millet. This study used Nongda 10 as material and adopt split-plot, the sowing date as the main plot and the plant density as subplot, the effects of sowing date and plant density on agronomy characters and yield components were invested. The results show that: there was a significant post relationship between grain yield and the number of spikes, the correlation coefficient was 0.93.The number of spikes was positively correlated with the plant density, and the correlation of coefficient was 0.54.However, the number of spikes decreased with the delay of sowing date, which mainly affected the tillers and spikes of the plant. Therefore, early sowing and increasing density are beneficial to improve grain yield of millet. The regression equation of yield, sowing time and density was Y=-55 547.13+886.29X₁+385.51X₂-3.37X₁²-2.86X₂²-1.39X₁X₂. Through finding the extreme value of the equation, we found that when sowing on May 5th and plant density was 3.738×10⁵plants/ha, the grain yield of Nongda10 reached the maximum of 6 558.21 kg/ha.