The invention discloses a method for predicting a wing crack propagation track, which belongs to the field of rock mass mechanical analysis, and comprises the following steps of: firstly, obtaining tip crack initiation angles of open cracks with different crack inclination angles in a compression-shear state through theoretical calculation in combination with test result correction; On the basis of the relation between the crack inclination angle and the crack initiation angle, determining the wing crack propagation track of the initial crack in the microsection, and then connecting the end points of the two wing cracks to form a new crack, namely an equivalent crack; And taking the equivalent fracture as the initial fracture, continuously determining the expansion of the next micro-section, and so on to obtain the expansion track of the wing fracture. The prediction result is well matched with the test result, and compared with a traditional method for determining the crack propagation track through mechanical calculation, the method can conveniently obtain the wing crack propagation track, and is simple, easy to understand and convenient to operate.