With the quadratic regress common rotational cmbination design, the relati-onship among the degree of thecorn's green withered disease and its sowing density,the nitrogenous fertilizer and phosphate fertilizer were studied and theregress model was built. The experiment result indicated that the main factor affecting the corn green withered disease isthe sowing density,then the nitrogenous fertilizer,whose alternate effect to the disease index is x1x2,x2x3. And at last thesimulated optimization was made to t...