Abstract: The law of precipitation for 825 alloy treated at 600—1050 ℃ was studied.The results showed that in this range of temperature, lots of M₂₃C₆ precipitated in the grain boundaries with the precipitation peak occured at the temperature of 750—800 ℃.The precipitated temperature of M₂₃C₆ was under 940 ℃.The phase of Ti C was formed at the temperature of 940—980 ℃, corresponding to the sites of grain boundaries.Furthermore, the Ti C generated by hot working existed in the original grain boundaries after dynamic recrystallization.And the completely dissolve temperature of Ti C was at 1070—1100 ℃ with the substrate microstructure of twin austenite.