Two phenolic acids P-hydroxy benzoic acid and cinnamic acid were designated as four concentrations (0, 50 μmol/L, 100 μmol/L, 150 μmol/L) to investigate the effects of phenoic acids on the growth and the activities of membrane protective enzymes of cucumber seedlings. The results showed that both phenolic acids inhibited the seedlings growth. The inhibitory effects were increased with the concentration of phenolic acids increasing and the time of treatment prolonging. Seedlings treated with A150 (P-hydroxy benzoic Two of the phenolic acids P-hydroxy benzoic acid and cinnamic acid were designated as four concentrations (0, 50 μmol / L, 100 μmol / L, 150 μmol / L) to investigate the effects of phenoic acids on the growth and the activities of membrane protective The inhibitory effects of the seedlings growth. The inhibitory effects were increased with the concentration of phenolic acids increasing and the time of treatment prolonging. Seedlings treated with A150 (P-hydroxy benzoic