Abstract： Objective To study the inducing apoptosis effect of a traditional Chinese medicine gambogic acid (GA) on Raji cell line and its mechanism. Methods The effect of GA on the proliferation of human peripheral blood mononuclear cells induced by lipopolysaccharide (LPS) was analyzed. Raji cells were treated with GA at different concentrations and times, and the inhibitory effect was detected by MTT assay.Apoptosis induced by GA was observed by Annexin V/PI doubling staining and flow cytometry assay.Mitochondrial membrane potential was measured by JC-1 assay. Activated Caspase-3, Caspase-8 and Caspase-9 in living Raji cells were measured by caspGLOWTM fluorescein staining kit and quantificated by flow cytometry. Results After incubation with GA, the proliferation rates of both normal blood mononuclear cells and Raji cells were dramatically inhibited in a concentration dependent manner. GA induced Raji cells to undergo apoptosis. GA decreased the mitochondrial membrane potential of Raji cells. GA increased the level of activated caspase 3, caspase 8, caspase 9 for 0.37 %, 33.57 %, 18.27 % in 24 h and 28.2 %, 69.2 %,76.7 % in 48 h respectively. Conclusion GA have an inhibitory effect on Raji cells, and can trigger apoptosis of Raji cells through both intrinsic and extrinsic pathways.