There are two valve seat installation structures for triple eccentric butterfly valves: 1. Body valve seat, and the butterfly plate sealing ring directly contacts the valve body for sealing. 2. The valve body is inlaid with an independent valve seat, the seat ring of the valve body and the valve plate sealing ring automatically fit and seal, and the valve seat sealing ring is pushed by the medium to seal more tightly and scientifically, extended service life, And realize bi-direction 1:1 sealing.