The invention provides a gas steam generator, which comprises a main body of the steam generator, a liner, a tap water inlet, a steam supplying outlet, a smoke exhaust pipe, a base, support legs and a burner, wherein the tap water inlet, the steam supplying outlet, the smoke exhaust pipe, the base and the support legs are arranged on one side of the main body; the burner is arranged below the base; the main body is cylindrical; the top end of the main body is provided with a safety valve, a pressure gauge and a pressure controller; the side wall of the main body is provided with an electronic controller panel and a water level controller; the burner adopts a safety control technology of controlling flames in a pure electronic manner; the water level of the water level controller is divided into a high water level, a middle water level and a low water level by built-in water level needles; and the side wall of the main body is also provided with a drain outlet, a flame viewing hole and a water supplement solenoid valve. The gas steam generator has the beneficial effects of intellectualization in mechanical operation, novel appearance, no deflagration phenomena, high safety, reasonable structure, small volume and high heat collection performance, and is convenient to clean.