Abstract: For science forecast that the suitable planting density of the foxtail millet, explores the mathematical prediction model of the foxtail millet planting density and grain yield. The main density on crop yield empirical model, a few fitting models were simulated and compared by employing field plot experiment and nonlinear regression analysis. The results showed that, the foxtail millet planting density on grain yield had important influence. The trend of foxtail millet grain yield with planting density increase was first increased then decreased. Through the model simulation and comparison, quadratic curve model was considered the optimal model that the foxtail millet density and yield relate. Predicted equation of spring sowing ‘Jigu 19’ and ‘Jigu 31’ respectively were yj19=2725.528+86.885x-0.701x2 and yj31=1289.529+131.318x-1.023x2, theoretically optimum density respectively were 619700 plants/hm2 and 641800 plants/hm2. This study had established a mathematical prediction model, which would provide the theoretical foundation for the spring foxtail millet production.