Abstract: Various defects with dispersive feature sizes can be accumulated inevitably in fiber-reinforced resin composites during their manufacturing and service processes, which are also difficult to be detected. The final objective of defects testing is to obtain the accuracy assessment of performance of defective structures. A micro-stress non-destructive defect detection and evaluation method is proposed for fiber-reinforced resin composites, which is especially suitable for composites measurement. Combing with the optical measurement technology for full-field displacement, the abnormal responses which caused by the defects of the structure under low stress level is able to be captured. The wrinkle defect detection is taken as an example to show the measurement processes. First, a specific detection scheme is designed based on the theoretical prediction of characteristic responses of wrinkles. Then, a new method of full-field displacement measurement is innovatively proposed based on the grating projection technology. Results show that under the axial tensile loading, the distorted out-of-plane displacements caused by wrinkles can be detected by the improved grating projection technology. The distorted displacements revealed the spatial distribution and severity of defects, and the influence on structural performance degradation can be evaluated based on the degree of displacement distortion. Further, by applying the optical-mechanical detection method, the mechanical responses of the defective component under a given working condition can be obtained directly, which can provide a reference for the adaptability evaluation of the component.