Abstract: The 4Cr5Mo2V steel was quenched at 1 000-1 090 ℃. The tempering hardness of the test steel quenched at the same temperature was adjusted to 55,52 HRC by tempering twice at different temperatures, and the effects of the quenching temperature and tempering process on the microstructure, impact toughness and high temperature (350 ℃) wear resistance were studied. The results show that when the tempering hardness was the same, too high or too low quenching temperatures would reduce the toughness of the test steel and aggravate the peeling of the wear surface material, thereby reduced the wear resistance. Under the same tempering hardness, the toughness and high temperature wear resistance of the test steel quenched at 1 030 ℃ were the best, and at 1 090 ℃ were the worst. When the quenching temperature was the same, the test steel tempered at relatively low temperatures had higher tempering hardness, which could support the surface oxide layer, so its wear resistance was better than that tempered at relatively high temperatures. The recommended heat treatment process for 4Cr5Mo2V steel was 1 030 ℃×30 min oil quenching +560 ℃×2 h tempering for twice.