Abstract: Synthesis of propyl-L-glutamine by glutamyltranspeptidase cells was investigated. With L-glutamlhydrine and propylamine as substrate, the factors such as substrate concentration, pH and temperature were investigated. The results indicated that when the concentration of L-glutamlhydrine was 0.4 mol/L, the concentration of propylamine was 3 mol/L, reaction temperature was 37ºC, and pH was 10, the yield of obtained propyl-L-glutamine reached 97.9%.The yield of propyl-L-glutamine was 85.3%. The purity of propyl-L-glutamine was 99.8%. Synthesis of propyl-L-glutamine by glutamyltranspeptidase cells was effective.