[Objective]To summarize professor CHENG Haibo's clinical experience in treating tumor metastasis with cancerous toxin pathogenesis theory. [Method] By following the teacher clinic and sorting out the related cases,the author summarizes professor CHENG Haibo's academic experience of treatment of tumor metastasis with cancerous toxin pathogenesis theory,and for proven cases. [Result] On the base of cancerous toxin pathogenesis theory and clinical practice,Professor CHENG Haibo puts forward that deficiency of vital qi and cancerous toxin inflowis the basic pathogenesis of tumor metastasis. Qi deficiency is the root cause of tumor metastasis and canceousr toxin inflow is the main pathogenesis of tumor metastasis. Canceousr toxin inflow has special channel,carrier and law,and supporting and invigorating Qi,anti-cancer and detoxificationis the main method of prevention and treatment of tumor metastasis. Professor CHENG Haibo treated a case of brain and liver metastasis in lung cancer with cancerous toxin pathogenesis theory before. And the curative effect was very remarkable. Brain and liver metastasis was significantly reduced.[Conclusion] Professor CHENG Haibo 's experience is effective and worthy of learning and promotion.