Abstract: In the previous research of the stress intensity factors for the branch crack of the closed flaw under compressive loading, the curve branch crack was often simplified as a straight crack, and the curve effects of the branch crack propagation path was always neglected. To overcome this deficiency, the curve branch crack model is set up based on the mathematical description of the curve branch crack propagation paths, in which the curve effects of the branch crack propagation paths are considered. By the model, the stress intensity factors of the branch crack are solved. Further more, the branch crack propagation process is simulated numerically by the secondary development of ABAQUS, and the stress intensity factors of the branch crack are obtained. And thereby the comparative analysis on the stress intensity factors by the curve branch crack model in the paper, by the numerical simulation and by the branch crack model in the previous research is carried out, which shows the validity and necessity of the curve branch crack model proposed in the paper.