The invention relates to the technical field of medicine, and discloses application of ovatifolin to preparation of lung cancer, liver cancer and colon cancer resisting drugs. The inhibiting effect of ovatifolin on the growth of a human lung cancer cell line A549, a human liver cancer cell line BEL-7402 and a human colon cancer cell line HT-29 is disclosed for the first time. The in-vitro growth inhibiting effect of ovatifolin on the human liver cancer cell line BEL-7402 and the human colon cancer cell line HT-29 is obviously higher than that of the positive drug TPT (topotecan hydrochloride). The in-vitro growth inhibiting effect of ovatifolin on the human lung cancer cell line A549 is close to that of the positive drug TPT (topotecan hydrochloride). Therefore, it is shown that ovatifolin has a remarkable anti-tumor effect on in-vitro lung cancer cells, liver cancer cells and colon cancer cells, and has broad medicinal prospects.