In order to investigate the antitumor effect of IL2 gene transfected tumor vaccine, gene transfected tumor cells which secrete IL2 in a comparatively sustained manner must be obtained. Their growth and metastatic characteristics must be identified. This study used the retrovirus infection method to introduce human IL2 cDNA into mouse B16 melanoma cells. Southern blot analysis confirmed the establishment of IL2-integrated B16 cells (B16-IL2). Northern blot also showed the expression of IL2 gene in mRNA level. IL2 secretion of B16-IL2 was comparatively stable for a period of 6 months with the highest production rate of 53u/ml. No obvious influence was observed on the morphology and growth of the tumor cells in vitro after the transfection of IL2-cDNA. But, their oncogenicity in vivo was reduced and the tumor growth induced by B16-IL2 cells was inhibited. Lung metastasis rate and extent was also reduced. This study laid the foundation for the preparation of an IL2-secreting tumor vaccine.