Abstract: Tumor microenvironment is a local environment closely related to tumor cell proliferation and metastasis， recent advances in tumor biology research emphasize the important role of tumor cell-derived exosome in the regulation of tumor microenvironment. It is suggested that cancer toxin is the key pathogenesis of tumor occurrence and development， and tumor microenvironment may be the biological basis of cancer poison pathogenesis theory. By comparing the generation， pathogenic characteristics and pathogenic mechanism of cancer toxin and tumor cell-derived exosome， it is believed that cancer toxin is closely related to tumor cell-derived exosome， which may be the biological basis of cancer toxin and pathogenesis. It is of great significance to further revealing the scientific connotation of cancer virus pathogenesis theory.