Abstract: Based on the sliding-crack-model and the previous study on the wing crack of the open flaw under compression, the propagation characteristics of the wing crack from the closed initial flaw is studied. Then some conclusions are drawn as the following: 1) With the propagation of the closed flaw, the wing crack path is gradually close to the line, which is parallel to the direction of the most compressive stress, called by the asymptote of the wing crack path. Then the asymptote equation is determined in the paper. Compared with the open flaw, the asymptote of the wing crack from the closed flaw does not pass though the center point of the initial flaw, and its location is related to the initial flaw length, the initial flaw inclination angle and the friction coefficient of the flaw surfaces. 2) Owing to the asymptotic characteristics, the propagation path of the wing crack can be described by a hyperbolic equation approximately, and the hyperbolic equation is determined in the paper. Furthermore, the propagation characteristics of the wing crack are analyzed by the secondary development of ABAQUS. Then the comparative analysis on the propagation loading and path is made by the hyperbolic equation, by the numerical simulation and by the experiments, and the results show the propagation loading and path by the hyperbolic equation are in concordance with those by the numerical and experimental results, which shows the validity of the results in the paper.