The invention discloses a prefabricated out-hung wall panel construction method. The method comprises steps of axis elevation recheck, base level elevation adjustment, positioning block mounting, preparation before lifting, out-hung wall panel lifting, out-hung wall panel inclined support mounting, out-hung wall panel correction, out-hung wall panel connector mounting, out-hung wall panel gap sealing and check and acceptance. The method of the invention can solve several common problems in construction, and has the control advantages of mold saving degree, quality controllable degree, gap precision, construction quality and safety. In addition, the prefabricated out-hung wall panel can be made into a standardized size, and the purpose of standardized production can be realized.