Damage mechanism of filament-wound composites is a challenging fundamental subject, which is a key to structural design and service performance evaluation of filament wound composite structures in aviation and aerospace engineering. This project will be studied by theoretical analysis, numerical simulation in conjunction with experiment test. Based on filament wound process analysis, a resin-fiber compaction model of filament wound composite is established and the initial defects are characterized. The extended multi-scale finite element method (EMSFEM) is employed to evaluate damage mechanism of filament-wound composite containing the initial defects due to manufacturing process. The EMSFEM model of filament wound composite is experimentally verified by the lock-in infrared thermography technique. Finally, a parametric analysis is conducted to study the damage evolution mechanisms of filament-wound composite containing the initial defects due to manufacturing process. The achievement in this project will contribute to trans-scale damage analysis theory and method for fiber reniforced compostes. Moreover, it is helpful to analysis, design, safety evaluation, life estimation and corresponding national standard of filament wound structures for Chinese aviation and aerospace engineering.