This article introduces a method of damage tolerance analysis of stiffened skin panel for civil aircraft,shown by an example of panel with two-bay longitudinal crack and center broken frame, taking into account three parts of factors: stiffening effect, bulging effect and the stress distribution. Stress intensity factor at each crack tip is derived from combination of above mentioned three factors. At last, the analysis of the crack growth in skin and the residual strength for the surrounding intact structures can be performed. One chosen example is calculated by this method, and the analysis results are compared to the relative test results, which show that the agreement between them is very good. The practicability and the feasibility of this method are proved.