The invention provides a gas valve with proportional electromagnetic valve regulation and combustor air pressure feedback regulation functions. The gas valve comprises a proportional valve and a self-suction valve. The upper end of an aluminum valve element of the proportional valve is connected with a valve clack, a valve deck is arranged at the lower end of a valve body, the periphery of a membrane is clamped between the valve body and the valve deck, the lower end of the aluminum valve element is connected with a center hole of the membrane, and the lower portion of the membrane is connected with an aluminum valve element reset mechanism; the valve deck is connected with a proportional electromagnetic valve which comprises a guide pipe, the upper portion of the guide pipe is connected with the valve deck, the lower portion of the guide pipe is connected with a lower valve base of the proportional electromagnetic valve, an exciting coil is connected to the outside of the guide pipe through a framework, a regulation movable core is assembled in the guide pipe, and a lower end cover is assembled at the inner hole in the lower section of the lower valve base; a shaft end is arranged at the lower end of the aluminum valve element and corresponds to the regulation movable core, the upper end of the regulation movable core abuts against a reset spring, the shaft end is sleeved with the reset spring, and the upper portion of the reset spring abuts against the valve deck; the lower end of the regulation movable core abuts against a pressure stabilization spring, the other end of the regulation movable core abuts against a lower end cover of the proportional electromagnetic valve, the side edge, corresponding to the pressure stabilization spring, of the lower valve base is connected with a feedback air pressure pipe joint, and the pipe joint is connected with a combustor. The gas valve is used for a gas water heater and has the advantage that output water temperature fluctuation is extremely small.