The invention provides an isolicoflavonol-containing antitumor drug, wherein suspension type injections, tablets and microcapsules are processed and manufactured by taking isolicoflavonol as the active ingredient and combining with pharmaceutically acceptable auxiliary materials and carriers. The antitumor drug is used for preventing and treating breast cancer, ovarian cancer, cervical cancer and colon cancer and usual gastrointestinal cancer, lung cancer, kidney cancer, bladder cancer, prostate cancer, skin cancer, head and neck cancer, brain tumor or leukemia. Confirmed by pharmacological experiments and antitumor effect comparing evaluation, the isolicoflavonol coming from traditional Chinese medicine liquorice has the function of inhibiting the generation of new blood vessels and is capable of achieving the purpose of resisting tumors through inhibiting the generation of the new blood vessels of the tumors. The invention provides an industrial preparation method of the isolicoflavonol serving as a medicinal material, comprising extraction, separation, grain size specification and other concrete process requirements.