This invention provides a polymer-bonded CA4 pharmaceutical compound and a preparation method therefor. The polymer-bonded CA4 drug provided in this invention has a structure represented by formula (I). With respect to the bonded pharmaceutical compound provided by this invention, CA4 is grafted onto a specific polymer carrier, so that the resultant bonded drug may be enriched in tumor vessels and the active drug is slowly released. Therefore, an efficacy of destroying tumor vessels is exerted at a tumor site for a long period, an excellent tumor inhibition effect is achieved, and the problem of poor therapeutic effects due to short action time of CA4P is effectively solved, and thus it has a broad prospect of development in the field of tumor treatment. Additionally, the preparation method provided in this invention is simple and has wide sources of raw materials, and it is possible to achieve scale production and industrialization.