Mouse FBL-3 erythroleukemia cells were transfected with recombinant human interleukin-6 (rhlL-6) gene and a clone secreting IL-6 was selected (i.e., FBL-3-IL-6⁺). The cell clone secreting IL-6 was inoculated into C57BL/6 mouse. The growth of tumors was observed and histologic analyses of the tumors in situ, liver, spleen and bone marrow were performed after inoculation. The mice inoculated with wild-type FBL-3 erythroleukemia cells were used as the control. The results showed that the later the tumor occurrence, the slower the tumor development, the lower the pathological changes degree and the longer the survival time in experimental group compared to that of the control. The results demonstrated that the inoculation of the FBL-3 cell clone secreting IL-6 can inhibit the invasion of leukemia cells, suggesting that the FBL-3-IL-6⁺ cells can be used as a vaccine to treat leukemia.