Aim: To analyze the effects of amyloid beta-protein precursor N end 328-332 on the growth of human neuroblastoma (HNB) SY5Y, and find in vitro the neurotrophic effects as well as the best concentration for growth of neurocytes, so as to provide the theoretical basis for the protection of cellular injury and in vivo research of medicament. Methods: Grouping: cells were divided into groups according to the experimental purpose: In the first step, cells were divided into control group, 2.5, 5, 10, 20, 40, 80, 160 μmol/L APP 5-mer peptide group. In the second step, they were divided into control group and 40 μmol/L APP 5-mer peptide group. MMT metabolic rate was used to determine the cell survival rate so as to screen the best concentration for promoting the growth of neurocytes. MMT metabolic rate was adopted to determine the survival rate of cells and cell counting to detect the cell growth and lactate dehydrogenase (LDH) leakage rate, so as to observe the cell death rate. The levels of P-CREB and Bcl-2 expression were inspected with Western Blotting and taken as the observation indicators. The effects of APP 5-mer peptide on HNB SY5Y growth. Results: 1 APP 5-mer peptide could promote the growth of SY5Y cells from 10 μmol/L, and the minimum concentration was 20 μmol/L, the effects of APP 5-mer peptide at 40 μmol/L was the best, and began to decrease at 80 μmol/L. Therefore, the concentration below 40 μmol /L was taken as the test concentration. 2 Compare with the normal control group, the A value of survival rate in administration group of 40 μmol/L APP 5-mer peptide group was much higher, and differences among groups were significant (0.974 1±0.004 7,0.600 1±0.001 9,P < 0.01). 3 The leaking rate of LDH in administration group of 40 μmol/L APP 5-mer peptide group was obviously lower than the control group, and there were remarkable differences among groups (84.913 5±31.575 9,199.625 2±40.727 3, P < 0.01). 4 From the 4th day of inoculation, the cell count of SY5Y cells in the APP 5-mer peptide group was significantly increased than the control group and differences were marked (P < 0.05). 5 The expression of Bcl-2 and P-CREB in 40 μmol/L APP 5-mer peptide group was higher than the control group (37 424.08±83.59, 34 957.24±78.03,19 110.24±45.80, 2 761.36 ±58.61, P < 0.05). Conclusion: APP 5-mer peptide has a neurotrophic effect on SY5Y cells, and the effects are better at 40 μmol/L than at other concentrations.