Abstract: The stress intensity factor is used in fracture mechanics to predict the stress state near the tip of a crack caused by a remote load or residual stresses. In this paper, the law between WC_P shape and its tip stress was established in a finite plate under uniaxial stress based on stress intensity factor, the thermal stress of WC_P/Fe compo-sites with different particle shapes were simulated through finite element analysis software, the effect of WC_P shape on the thermal fatigue crack propagation behavior of WC_P composites was studied. The results show that the WC_P shape significantly affects the stress intensity factor and the thermal fatigue crack propagation behavior of WC_P/Fe composites. The ultimate compressive strength of WC_P/Fe composites with spherical particles and irregular ones are 460 MPa and 370 MPa, respectively. The WC_P/Fe composites with irregular particles are prone to break due to stress concentration resulting in generating brittle cracking. The thermal shock test was used to verify the simulation results, finding that the experimental results are similar to the simulation results, which confirms the correctness of finite element simulation, and provides a scientific and theoretical basis for the study of thermal fatigue crack propagation behavior of WC_P/Fe composites.