Abstract: The method for improving mechanical properties of heat resistant steel by means of both equal-channel angular pressing(ECAP) and heat treatment was investigated.The mechanical properties were not improved by technics of solution + temper after ECAP,but were greatly improved by technics of solution + temper + ECAP + temper.Yield strength was raised about 60% at the low limit temperature of its specification,and the ductility satisfied the specification.The remarkable improvement of strength was caused by working hardening.At the upper limit temperature of its specification,recrystallization occurred,the grain size was fined significantly,both the strength and ductility were improved a little.