A pot experiment was conducted to evaluate the effects of applying L-methionine (L-MET), L-phenylalanine (LPHE) and L-tryptophan (L-TRP) on the growth of Zea mays and its nutrient uptake, and to determine the optimal application rate of them. The results showed that L-MET, L-PHE and L-TRP could improve the shoot height, shoot and root dry weights, root activity, nitrate reductase and hydrogen peroxidase activities, and N, P, K and Zn uptake of corn. The optimal application rate of L-MET, L- PHE and L-TRP was 0.0185 - 0.185 mg x kg)(-1) soil, 0.2 mg x kg(-1) soil, and 0.03 - 0.3 mg x kg(-1) soil, respectively, and L-PHE and L-TRP were superior to L-MET.