The invention relates to a medicinal composition for treating cancer and use thereof and belongs to the field of chemical medicaments. To solve the technical problem, the invention provides a medicinal composition for treating cancer. The medicinal composition for treating cancer comprises the following active ingredient of tetravalent V inorganic acid salt. Compared with like medicaments in market, the medicament has the advantages of obviously reducing the cost and lightening economical burden of a patient. Clinical researches prove that: the medicament does not have obvious toxic or side effect or increase pain to the body of the patient. The medicament has higher recovery rate, is a new option for treating the cancer, and has wide market prospect.