The thermal fatigue properties of three H13 steel samples were investigated by scanning electron microscope ( SEM) and X-ray diffraction ( XRD) . And the samples were treated by multicomponent permeating, gas nitriding, quenching and tempering, respectively. It is indicated that the H13 steel after RE-N-C-S-V-Nb multicomponent permeating treatment has much better thermal fatigue resistance performance according to the crack 爷 s characteristic and structure. The strengthening effects of fine-grain and dislocation by RE-N-C-S-V-Nb multicomponent permeating treatment, and their influence on the thermostability, high temperature hardness and oxidation resistance, are discussed. The strengthening mechanism on the thermal fatigue performance is revealed theoretically.