The invention discloses an adjustable leg traction brace for orthopedic surgery. The adjustable leg traction brace comprises an adjusting frame, a support surface and a traction mechanism, wherein side walls are arranged on two sides of a bottom seat and two sides of a top seat of the adjusting frame respectively, sliding holes and fixed holes are formed in the side walls, a lower sliding shaft and an upper sliding shaft are mounted in the sliding holes in the bottom and top side walls respectively, a lower fixed shaft and an upper fixed shaft are mounted in the fixed holes in the bottom and top side walls respectively, two pairs of swing plates are hinged to the corresponding sliding shafts and fixed shafts, and oblique fulcrum bars and the support surface are hinged to two sides of the front end of the top seat. By means of three takeup wheels on an upright column, height adjustment of the adjusting frame and traction fixation of ankles and knees are realized respectively, and the operation is quite convenient. The adjusting frame drives the brace to lift through cooperation of a spool and a bracing wire, and labor is saved greatly.