Abstract: In order to predict the strength and damage revolution situation of large opening composite structures, the applied research of the three kinds of different composite material 3D damage degradation models (sudden degradation model, progressive damage model and continuum damage model) used in the prediction of the strength of large opening composite structures were conducted. In-plane pure shear test of large opening composite structure with frame reinforcer was carried out, and the three kinds of damage degradation models were used to numerically simulate the calculation examples of test specimen and relative reference. The comparison between numerical simulation results and experiment results shows that each of the three damage degradation models can predict the ultimate strength of large opening composite structures relatively accurately. Continuum damage model has the highest accuracy, best universality and lowest mesh dependency comparing to other models. The research results could provide theoretical guidance for the investigation of mechanical properties of large opening composite structures.