Abstract: By analyzing the thermal/mechanical simulation test data under dynamic recrystallization (DRX) of cold heading steel SCM435 in a temperature range of 950 to 1 150% and a strain rate range of 0.1 to 1 s^-1 such characteristic Values as critical strain ε_c,peak strain ε_p,critical stress σ_c and peak stress σ_p.were derived from the curves of strain hardening rate to flow stress (θ-σ).The Avrami kinetic curves of dynamic recrystallization and the time exponent n of SCM435 steel were calculated by the stress-strain (σ-ε) method.It is shown that the average value of ε_c/ε_p,is 0.73 and the average value of n was 1.91 under DRX.The DRX Avrami kinetic of SCM435 steel is sensitive to strain rate and not temperature-sensitive in the temperature range of 950 to 1 150% and the strain rate of 0.1 to 1 s^-1.The time when the crystallization ratio is 50% is inversely proportional to strain rate.