Fuel gas/air proportion control valve

The utility model provides a fuel gas/air proportion control valve comprising a valve body (17) provided with an air inlet (19) and an air outlet (20), as well as an A valve cavity (1), a B valve cavity (2), a C valve cavity (3), a fuel gas passage I (4) and a fuel gas passage II (5) which are sequentially communicated in the valve body (17), and an F valve cavity (23) and a H valve cavity (13) which are communicated with the fuel gas passage II (5) respectively, wherein the F valve cavity (23)is communicated with the H valve cavity (13); the air inlet (19) is communicated with the A valve cavity (1); and the air outlet (20) is communicated with the F valve cavity (23). The fuel gas/air proportion control valve is characterized in that an electromagnetic valve SV 1 (11) and an electromagnetic valve SV 2 (12) are arranged on a passage between the A valve cavity (1) and the B valve cavity (2) and a passage between the B valve cavity (2) and the C valve cavity (3) respectively; and a servo valve SV3 (9) is arran