The invention discloses an energy-saving combustion furnace for heating and ventilation heating. Fixing shafts are arranged in a furnace wall on the two sides of the interior of the furnace wall respectively; a grate is installed on the fixing shafts and is fixedly connected with the fixing shafts; a furnace slag discharge shaft is installed just below the grate in the furnace wall through bearings; five beaters are arranged on the furnace slag discharge shaft and can discharge furnace slag after combustion; a furnace bottom door is formed in the bottom of the furnace wall and formed in the furnace wall through a hinge; a furnace mouth is formed in the top part of the furnace wall; and exhaust cylinders are arranged on the two sides of the furnace mouth and communicate with the interior of the furnace wall. The energy-saving combustion furnace is scientific and reasonable in design, simple in structural composition and convenient in use and has very wide application prospect.