Abstract: Crack propagation of UAV wing's ribs has been simulated by ABAQUS secondary development using Python language. In the study, the wing rib is reduced to two-dimensional slab structure, the crack is placed at the connection of the beam and rib, and the crack propagation process of different initial angle is simulated. The results have been obtained, that crack propagation morphology, variation of stress intensity factor in the expansion process and crack propagation angle, has close relationship with the crack location and initial crack angle. Crack propagation morphology can be divided into two kinds generally, one is along the initial direction when the initial crack angle between 50°and 70°, another is crack towards the lower surface of rib ultimately when the initial crack angle between -70° and 40°. The results have a certain reference value on crack growth rate and crack arrest of the wing ribs.