The invention discloses a smokeless barbecue oven, which comprises a barbecue oven main body, an arched heat conduction device and an ash collection device, wherein the barbecue oven main body comprises a barbecue box and a barbecue rack which is used for supporting the barbecue box and is detachably connected to the barbecue box; a groove is formed in the sidewall of each of two long sides of the barbecue box; a plurality of ash passing holes are formed in the bottom of the barbecue box; at the bottom of the barbecue box, two support frames are additionally arranged on the left and right sides of the barbecue box; the arched heat conduction device is arranged above the barbecue box, and two ends of the arched heat conduction device are embedded in the grooves; and the ash collection device is detachably erected between the two support frames. The smokeless barbecue oven provided by the invention can protect air from being polluted due to the generation of a great amount of smoke in the case that excessive oil stains or water drop onto barbecue charcoals; by connecting the ash collecting device and the barbecue box in a detachable mode, ash can be collected and processed conveniently; and in addition, the height of the barbecue rack can be regulated in accordance with the body heights of barbecue operators, so that the comfort in a barbecue process is enhanced.