The invention relates to a triterpenoid compound as shown below and a preparation method and use thereof. It is shown through several in vitro immunosuppressive activity tests that the compound has anobvious effect on inhibiting lymphocyte proliferation in mice and are expected to be used in the preparation of immunosuppressive drugs. The triterpenoid compound and the preparation method and use thereof can provide lead compounds for the development of new drugs for the treatment of autoimmune diseases and organ transplant rejection.