Abstract: Based on the dynamic materials model theories, hyperbolic sine equation and two Liapunov stability criteria, the processing maps of T122 heat resistant steel were constructed using the data obtained from isothermal hot compress tests by means of a Gleeble 3 500 simulator. The hot formability of the T122 steel was studied and its relations with microstructure at various temperatures and strain rates were analyzed using the process maps. The result shows that the efficiency of power dissipation increases with the increase in temperature and the decrease in strain rate, The T122 steel exhibited dynamic recrystallization with a peak power dissipation efficiency of 0.2 occurring at the temperature upwards 1085℃ and the strain rate less than 0.37 s^-1 The temperature of 1085~1150℃ and the strain rate more than 0.13 s^-1 are recommended to set the industrial forming conditions.