Abstract： Objective To prepare the mB7-1-GPI-anchored Lewis vaccine and investigate its antitumor effects. Methods mB7-1-GPI was incorporated on Lewis tumor cells and mB7-1-GPI-anchoring tumor vaccine was prepared. The anti-tumor immunity induced by the prepared mB7-1-GPI-anchored Lewis tumor cell vaccine in tumor-bearing mice was observed. Results Flow cytometric analysis showed that mB7-1-GPI were positively expressed on the surface of Lewis tumor cells. After Lewis tumor cells incubated with mB7-1-GPI, the positive rate (PR) of mB7-1 antigen was 95.8% (0h), 93.6% (4h), 91.1% (8h) and the fluorescence intensity (FI) was 11.2(0h), 10. 6(4h), 9. 8(8h). The IL-2 and IFN-γ production of splenic lymphocytes + lewis cells was (25.9 ± 1.4) pg/ml, (56. 0± 3. 5 ) pg/ml. The IL-2 and IFN-γ production of splenic lymphocytes + lewis/mB7-1-GPI was ( 871.3 ± 10. 4 ) pg/ml, ( 1329. 0 ± 11.9 ) pg/ml. In 25 days, the mean diameter of tumor of Lewis/mB7-1 -GPI was shorter than Lewis( 1.4 ± 0. 21 )cm & ( 2. 5 ± 0. 27 )cm , P ＜ 0. 05 ). Lewis tumor cell-bearing C57BL/6 mice treated with Lewis/mB7-1-GPI vaccine survived much longer than mice treated with Lewis vaccine ( 75.2 ± 2. 0 ) d & (40. 2 ± 2. 0 ) d ( P ＜ 0. 05 ). Conclusion The Lewis tumor vaccine prepared with mB7-1-GPI fusion protein significantly inhibited the tumor growth in Lewis bearing mice. It represented an useful new strategy for attaching immunological factor onto tumor cell surfaces without genetic manipulation.