Objective To study the influence of Haishengsu on cell growth and the expression of apoptosis gene in leukemia K562 cells by Haishengsu. Methods K562 cells were cultured in RPMI1640 containing 10% fetal bovine serum at 37℃ in a humidified atmosphere with 5% CO2. The experiment was performed on three groups: the control group and two Haishengsu groups (10mg/L and 20mg/L).The cell cycle, growth and the expression of Bcl-2 and bax were evaluated respectively by means of flow cytometer(FCM), thiazoyl blue tetrazolium bromide(MTT)assay and immunocytochemistry to determine Haishengsu’s influence. Results Both the Haishengsu (10mg/L and 20mg/L), restrained cell cycle in G1/S phase. The 20mg/L inhibited the growth of K562 cells and the survival of cells declined along with the time in this concentration. It was observed under light microscope that the number of positive cells increased in the two Haishengsu groups(20mg/L and 40mg/L).It was analyzed by image analysis instrument that the expression of Bcl-2 proportion decreased to (58.78±4.65)% and (26.57±2.13)% respectively in the Haishengsu groups (20mg/L and 40mg/L) from (90.98±8.66)% in the control group and the expression of bax proportion increased to (77.69±3.55)% and (90.60±3.73)% respectively in the Haishengsu groups (20mg/L and 40mg/L) from (10.88±6.57)% in the control group.Haishengsu (20mg/L and 40mg/L) could downregulate the expression of Bcl-2 and upregulate the expression of bax in K562 cells. Conclusion Haishengsu could significally restrain the cell cycle in G1/S phase and inhibit the growth of K562 cells. Haishengsu could reduce the expression of Bcl-2 and increase th