The invention relates to a quenching furnace with an impurity removal function. The quenching furnace comprises a main body, a cover plate, a heating chamber, a lifting plate, a quenching chamber, twoair cylinders, a stirring mechanism and an impurity removal mechanism, wherein the impurity removal mechanism comprises a filter screen, a transmission assembly, two driving assemblies and two impurity removal assemblies; each impurity removing assembly comprises a circular ring, a collecting box, a connecting pipe, a first branch pipe, a second branch pipe, a piston, a spring, a fixing ring, a first bearing, two fixing rods and a plurality of suction nozzles; each driving assembly comprises a transmission shaft, a one-way bearing, a driving shaft, a driving disc, a driving rope and two second bearings; and the stirring mechanism comprises a motor, a stirring shaft, a transmission gear, a third bearing and a plurality of stirring plates. According to the quenching furnace with the impurity removal function, the impurity removal function on quenching liquid is achieved through the impurity removal mechanism, the situation that impurities in the quenching liquid influence the quenchingquality is avoided, and the stirring function on the quenching liquid is achieved through the stirring mechanism, so that a workpiece makes full contact with the quenching liquid, and accordingly thequenching efficiency is improved.