It was attempted to improve wear resistance and durability under the load surface pressure that make a formation of the thick (mm-order) hard-surfacing layer for aluminum alloy of 5083. The thick hard layers were formed on the surface of 5083 by TIG overlay method. Al-(25.4, 33.6, 45.7 mass%) Cu filler metals which were newly developed were overlaid on two base metals forming the one bead, one layer and two layers. The investigation was made on the characteristics of hardening and wear resistance in relation to the microstructure of overlaid layers with selection of optimum overlaying condition.