In this research first the analysis of integrally stiffened panel has been made using FE code ANSYS. Hoop, Axial and Radial stress are calculated for the stiffened panel subjected to internal pressure. Secondly, crack growth characteristics of the integrally stiffened panel and conventional stiffened panel based on fracture mechanics and FE analysis are investigated. A fourteen-stringer stiffened panel is analyzed for a central skin crack propagating towards the adjacent stringers. Stress intensity factors and fatigue crack propagation rates of both types of the stiffened panels are then compared. The analyses result show that integral stiffening cause higher stress intensity factor than conventional stiffened panel as the crack tip passes through the stringer and the integral stiffened panel has less damage tolerance capability than the riveted stiffened panel. Finally, the FE analysis of repaired integrally stiffened aluminum alloy panel with a circumferential crack has performed in ANSYS. The analysis results depict that the maximum von Mises stress in each component of the repaired panel is below the yield strength of the Al alloy so the repaired method is successful.