Malignant tumor is one of the main diseases endangering human health at present. It not only brings great economic pressure to patients, their families and society, but also is a difficult problem that has not been completely solved in the medical field. Therefore, there is an urgent need to find a new and costeffective treatment for the benefit of the majority of tumor patients. At present, the combined use of multidisciplinary comprehensive therapy in the treatment of tumors has gradually become the consensus of the industry. The therapeutic application of ozone has a long history and began during the first World War. With the extensive application of ozone in the treatment of intervertebral disc herniation, peripheral artery obstructive disease, agerelated macular degeneration, dental related diseases and so on, ozone has gradually entered the field of vision of oncologists. Ozone therapy has been used as an auxiliary treatment for malignant tumors since the 1980s, but its effectiveness and mechanism are not yet clear. Combined with the relevant research of our group, and reviewing other reports at home and abroad, this paper will summarize the research progress of medical ozone in the treatment of tumor from three aspects: in vitro experiment, animal experiment and clinical research. To explore the effectiveness of ozone in the treatment of tumors and its possible mechanism.