The hot air furnace adopts orthogonal countercurrent heat exchange mode, integrates combustion and heat exchange, and sets waste heat recovery device at the smoke outlet (obtained national patent).This furnace is used for fuel gas combustion machine imported as heating, hot air temperature can be run within the range of 60-230 ℃, and hot air heating in the pure air, sent to broader range suitable for melon seeds, peanuts, almonds, pecans, pistachios, roots, fruit and other food and tea, aquatic products and other agricultural and sideline products, paper products, medicine, high-grade chemical, wood, etc in the field of drying and baking work.