The invention discloses a beta-carboline derivative targeted to CDK and DNA and a preparation method and medical application thereof. The beta-carboline derivative has a structure shown in the general formula I in the description. The compound can be applied in combination with other antitumor drugs and can also be applied in combination with radiotherapy. The antitumor drugs or radiotherapy and the compound can be applied at the same time or at different times. The combined therapy can perform a synergistic effect, and thus the therapeutic effect can be easily improved.