The aim of the present study was to investigate the anti-proliferation and pro-apoptosis effect of Coix lachrymajobi L varma-yuan on acute T lymphoblast leukemia cell line Jurkat cells and its mechanism. Jurkat cells were treated with Coix lachrymajobi L varma-yuan of various concentrations (0, 0.4, 0.8, 1.6 mg/ml) for 24h. The inhibitory ratio was measured by Cell Counting Kit-8. The effects of Coix lachrymajobi L varma-yuan on apoptosis of Jurkat cells were determined by Hoechst 33258, PI and Annexin V-FITC/PI double staining. The mitochondrial membrane potential was analyzed by JC-1 staining. The results demonstrated that Coix lachrymajobi L varma-yuan inhibited the proliferation of Jurkat cells, and induced chromatin condensation and fragmentation (characteristic of apoptosis) and loss of mitochondrial membrane potential. In conclusion, Coix lachrymajobi L varma-yuan can inhibit the cell proliferation and induce the apoptosis of Jurkat cells. These effects relate to loss of mitochondrial membrane potential. These results suggest that Coix lachrymajobi L varma-yuan may be of value in treating lymphoma.