Energy-saving gas-steam boiler

The invention discloses an energy-saving gas-steam boiler which comprises a boiler body, a plane premixing water-cooling gas burner arranged at the front end of the boiler body and a double-function energy saver arranged on the rear portion of the boiler body, the gas outlet side of the plane premixing water-cooling gas burner is connected with a boiler furnace, and the outlet side of the boiler furnace is connected with a high-temperature inner fin heat exchange pipe. The double-function energy saver is composed of a water chamber, a smoke inner fin heat exchange pipe arranged on the water chamber and an air inner fin heat exchange pipe arranged on the water chamber, a vertical steam-water separator is arranged on the upper portion of the boiler barrel, and a steam main pipeline used for conveying steam is arranged at the steam outlet end of the vertical steam-water separator. NOX in the generated flue gas is less than 30mg/m < 3 >, flue gas treatment equipment at the tail part of the boiler is saved, the vo