To investigate the anti-tumor and side effect of CpG ODN 1826 and CpG ODN2006 as an adjuvants on leukemic tumor in mouse-models, an acute lymphocytic leukemic tumor in mouse model was established, then inoculated inactivated L1210 cells alone or with different vaccine adjuvants were injected subcutaneously into each DBA/2 model mouse at different times. The activities of mice, the tumor formation rate and the growth status of leukemic tumor were observed. The tumor was examined by pathologic section. The results showed that the vaccine of inactivated L1210 cells and CpG ODN 1826 could decrease the leukemic tumor formation rate, slow down the growth of leukemic tumor mass in mice and obviously cause necrosis of tumor cells, but it could not prolong the life spans of the tumor-burden mice; while CpG ODN2006 could not only decrease the tumor formation rate, slow down the growth of tumor mass in mice and result in obvious necrosis of tumor cells, but also could eliminate the existing tumor mass in mice, and prolong the life spans of the tumor-burden mice. It is concluded that using CpG ODN2006 as an adjuvant enhances the anti-tumor effect against the leukemic tumor, prolong the life span of tumor-burden mice without obvious side effect.