Abstract: Taking three typical cold working die steels (DC53 steel, Cr8Mo2SiV steel, Calmax steel) as research objects, the content and distribution of residual austenite, impact toughness and dimensional stability after typical heat treatment process were compared, and the influence of residual austenite on the latter two was summarized. The results show that both the residual austenite content of DC53 steel and Cr8Mo2SiV steel were much higher than that of Calmax steel, and the content of residual austenite can be greatly increased by low temperature tempering at 400 ℃. The impact toughness of the cold work die steel after typical heat treatment was directly proportional to the content of residual austenite and inversely proportional to the tempering temperature. Both the size changes of DC53 steel and Cr8Mo2SiV steel followed the law of linear rising, while the size change of Calmax steel was not obvious.