The invention relates to the technical field of heat treatment on metal materials and in particular relates to a continuous hot air tempering furnace. The continuous hot air tempering furnace comprises a tempering furnace body and a transmission mechanism, wherein the transmission mechanism comprises a feeding unit, a conveying unit and a discharging unit; the feeding unit comprises a feeding rack, a feeding power device, a feeding driving roller, a feeding driven roller and a feeding belt; the discharging unit comprises a discharging rack, a discharging power device, a discharging driving roller, a discharging driven roller and a discharging belt; the conveying unit comprises a conveying power device, a roller set, a screen belt and a tensioning device; the roller set comprises an incoming end roller, an outgoing end roller, an adjusting roller and two circulation rollers; the tensioning device is in transmission connection with the adjusting roller; the tensioning degree of the screen belt is controlled by adjusting the relative position of the adjusting roller; a feeding slope platform is fixed on the feeding rack; a discharging slope platform is fixed on the discharging rack. The continuous hot air tempering furnace is low in heat loss, is incapable of causing scald to operators and is capable of effectively ensuring the tensioning degree of the screen belt.