The stress intensity factors of the integral wing beam structure with stopping-crack stringer are researched by use of FEM software ANSYS, and the crack propagating tests are achieved using simulate specimen. Results indicate that the value of the stress intensity factors have been a sharp decline due to the normal stress in the beam is shared by the stringer, and which is ability to share high static load so as to achieve fail-safe design before the crack extend to the stringer, nevertheless it is hard to stop the crack propagation by stringer. Beside, the shear stress in beam plate can’t serves to propagate model II crack since the ratio of the shear stress to the normal stress is smaller.