The invention relates to an application of a polycyclic compound to preparation of antitumor drugs and the antitumor drugs, and belongs to the technical field of the antitumor drugs. In order to solvethe technical problem, the invention provides the application of a polycyclic compound to preparation of antitumor drugs. The structural formula of the polycyclic compound is shown as the formula I.The invention finds a compound molecule having tumor inhibition cell proliferation. The molecule has good inhibitory activity on tumor cells of lung cancer, liver cancer, pancreatic cancer or colon cancer and the like, can be used for preparing the antitumor drugs, and provides new selection for the antitumor drugs.