Abstract: Objective 　To explore the effect of arsenic t rioxide (As2O3 ) in inhibition of proliferation、induc2 tion of apoptosis and it s potential mechanism. Methods 　The growth inhibition of As2O3 on FU97 was de2 termined by MTT assay. Apoptosis of FU97 induced by As2 O3 was investigated by DNA gel elect ro2 phore. The cell cycle alteration and apoptotic rate of the cells were measured by flow cytomet ry. The ex2 pressions of AFP、VEGF、STAT3 were determined by chemist ryluminescence 、Real2time PCR and EL ISA. Results 　The inhibitory effect of As2O3 on proliferation of FU97 cells was significant as revealed by MTT. DNA gel elect rophore show a marked DNA ladder. A typical sub2diploid peak before G0 / G1 phase was observed by flow cytomet ry. The effect of As2O3 on FU97 showed a remarkable cell cycle spe2 cificity, which indicates that As2 O3 mainly act s in G2/ M phase. Chemist ryluminescence, Real2time PCR and EL ISA showed As2O3 could obviously decrease AFP、VEGF and STAT3 protein production in FU97 cells. Conclusion 　As2 O3 can inhibit FU97 cells growth via apoptosis induction and cell cycle arrest . As2O3 inhibit s the metastasis of alpha2fetoprotein2producing gast ric carcinoma through reducing the ex2 pression of AFP、VEGF and STAT3.