Abstract: A spontaneous breast adenocarcinome developed in a NC nu/+ mouse was seccessfully serially transplanted subcutaneously into NC nude mice for 12 passages. Totally there were 27 animalstrans planted, and the transplantabity was found to be 1000％. Studies about the properties of growth and metastasis of it illustracted that the transplantability is high, the latest period is comparatively short and stable, the development is tepid, the tumor stroma is sich of blood vessels, and the occurrence of spontaneotus Iung metastasis is frequent(in our Work it was 100％). Its expression of highly metastatic rate was found to be not influenced by the animal sex. The establishment of this tumor model is considered to be useful for studying of metastatic mechanism of tumor and elucidation of the relationship betwccn tumor metastasis and vascularization in the tumor stroma.