Abstract: The effect of cold rolling deformation on microstructure and mechanical properties of 00Cr22Ni24Cu1Co1 heat resistant steel was studied by using optical microscope, scanning electron microscope, hardness test and impact test.The results show that after cold rolling with different deformation, solid solution at 1200 ℃×30 min and aging at 720 ℃×96 h, with the increase of rolling deformation, the grain size of the steel decreases, the microstructure uniformity increases, and the size of precipitates at grain boundary decreases.Compared with that before the aging, the impact toughness of the steel without cold rolling and cold rolling with 20% deformation+aging decreases by 75.2% and 48.1% respectively.The impact toughness of the steel with cold rolled deformation is significantly smaller.Cold rolling deformation is helpful to improve the toughness of the steel under high temperature aging.