Objective To study the effects of acetylcholine combined with vincristine (VCR) on A549 cells, furthermore to study the influence that is due to affecting the expression of the two proteins bcl-2 and p53. Methods MTT assay was used to analyze growth inhibition effect of acetylcholine alone and combined with IC50VCR on A549 cells.The expression of bcl-2 and p53 was measured by immunohistological chemistry technique(IHC) and Western blot.Results The inhibition rates for A549 cells with 0.1,1 and 10 μmol/L acetylcholine were (0.050±0.032)％,(0.101±0.021)％,(0.169±0.015)％.The inhibition rates for tumor cells with 0.1,1 and 10 μmol/L acetylcholine joint 0.2 μg/ml VCR were (0.529±0.023)％,(0.545±0.011)％,(0.589±0.015)％,the difference was statistically significant compared with the VCR group (q'values were 1.09,1.37,1.83,P＜0.05).Acetylcholine alone exerted inhibitory effect on A549 cells in a concentration dependent manner and significanrtly enhanced its sensitivity to VCR (P＜0.05).acetylcholibne (0.1-10 μmol/L)combined with IC50VCR decrased the expression of bcl-2 and p53 (P＜0.05).Conclusion Acetylcholine alone and combined with VCR can inhibit the growth of A549 cells. Significant synergistic effect between acetylcholine and VCR is found in inducing cell apoptosis by changing the expression of bcl-2 and p53.