To investigate the effect of Tanshinone IIA on apoptosis of leukemic cancer cells and tumor growth inhibition in vivo. Human leukemia cell line HL-60 cells were divided into model group, low-dose group, medium dose group and high-dose group and transfected according to the groups. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide method was used to calculate the inhibition rate of cell growth, flow cytometry was used to detect the apoptosis rate and mitochondrial membrane potential and Western blot was used to detect mitochondrial membrane potential related protein. The treatment group was treated with Tanshinone IIA and the control group was given phosphate-buffered saline+dimethyl sulfoxide intraperitoneal injection. 2 w later, the tumor size and weight were measured and weighed. The 24 h and 48 h proliferation inhibition rates of the experimental group were significantly higher than those of the model group and increased with the increase of the dose (p<0.05). The early apoptosis rate and late apoptosis rate of the experimental group were significantly higher than those of the model group and increased with the increase of the dose (p<0.05). The level of integral optical density in the experimental group was significantly lower than that in the model group and decreased with the increase of the dose (p<0.05). The levels of caspase-9, caspase-3 and B-cell lymphoma 2 related X protein in the experimental group were significantly higher than those in the model group, while the level of B-cell lymphoma 2 in the experimental group was significantly lower than that in the model group and there was drug dependence (p<0.05). The tumor size and weight of the treatment group were significantly lower than those of the control group (p<0.05). Tanshinone IIA can induce apoptosis and tumor growth of leukemia cancer cells in vivo and slow down the proliferation of cancer cells, which may be related to the regulation of mitochondrial pathway and the inhibition of mitochondrial membrane potential related protein.