Factor quadratic regression with 3 general rotation designs was adopted to study the effects of Fe, Mn and Zn fertilizers on the growth of eggplant, and the regression model was obtained among yields and 3 factors. The results showed that the influence of 3 factors on eggplant yield was in order of Mn> Fe> Zn. There were interactions among various factors. Fe and Mn, Fe and Zn, and Mn and Zn had positive correlations to yield below levels of fertilization 0.525 and 1.268, 0.525 and 0.416, 1.268 and 0.416, but had negative correlation when levels of fertilization being higher. The highest yield of eggplant was 34.62 t/hm2 based on computer simulation, corresponding to the fertilizer amounts of Fe, Mn and Zn were 47.85 kg/hm2, 35.85 kg/hm2 and 6.15 kg/hm2, respectively. The established model was validated accurately and reliably by tests.