1. Classified by structure (1) Central sealing butterfly valve (2) Single eccentric sealing butterfly valve (3) Double eccentric sealing butterfly valve (4) Three eccentric sealing butterfly valve 2. According to the sealing surface material classification (1) soft sealing butterfly valve. 1) The sealing pair is made of non-metallic soft material to non-metallic soft material. 2) The sealing pair is made of metal hard material to non-metal soft material. (2) metal seal butterfly valve. The sealing pair is made of metal hard material to metal hard material. 3. Classified by seal (1) Forced seal butterfly valve 1) Elastomeric seal butterfly valve. Sealing pressure ratio by the valve is closed when the valve plate squeeze valve seat, valve seat or valve plate flexibility 2) plus torque sealing butterfly valve. Sealing than the pressure applied by the valve shaft torque (2) pressure sealing butterfly valve. Sealing than the pressure from the valve seat or valve plate elastic seal components generated pressure (3) automatic sealing butterfly valve. Sealing pressure is automatically generated by the media pressure. 4. Classified by working pressure (1) Vacuum butterfly valve. Work pressure is lower than the standard reactor atmosphere calendar butterfly valve. (2) low pressure butterfly valve. Butterfly valve with nominal pressure PN <1.6MPa. (3) medium pressure butterfly valve. Nominal pressure PN 2.5 - 6.4MPa butterfly valve. (4) high pressure butterfly valve. Nominal pressure PN 10.0 - 80.0MPa butterfly valve. (5) Ultra-high pressure butterfly valve. Nominal pressure PN> 100MPa butterfly valve. 5. Classified by working temperature (1) High temperature butterfly valve. Butterfly valves with t> 450 C (2) Medium temperature butterfly valves. Butterfly valves of 120 C <t <450 C (3) Normal temperature butterfly valves. A 40C <t <; 120 C butterfly valve (4) low temperature butterfly valve. A 100 <t <a 40 C butterfly valve (E) ultra-low temperature butterfly valve. t <a 100 C butterfly valve 6. According to the connection classification (1) on the butterfly valve. (2) Flanged butterfly valve. (3) Bellow butterfly valve. (4) welded butterfly valve.