Abstract: Fiber reinforced composites are widely used in many fields. One notable application is the solid-rocket motor case. Therefore,predicting its stress and strength is extremely important. A failure analysis for predicting local damage of the structure amd making the stiffness degradation is essential to composite structures. A model with the nonlinear finite element theory was used to calculate some solid rocket motor case. Excellent agreement was found between the numerical results amd the tested ones. This method can be used to analyze the structure of filament wound composites.