Abstract: Continuous SiC fiber reinforced SiC matrix composites (SiC/SiC) have good application prospects in the nuclear engineering structures, due to their excellent high-temperature mechanical properties, irradiation stability and low helium permeability. Understanding the damage evolution mechanism and the strength is significant for the application of SiC/SiC composites. Based on the multi-scale characteristics of the fabrication process and component material distribution of plain woven SiC/SiC composites, fiber-scale (the fiber yarn model) and yarn-scale (the woven fabric model) unit cell models were established considering the local periodicity of the microstructure of the composites. In this paper, finite element method was applied to predict the elastic properties and strength properties of the fiber-scale model, which were then substituted into the yarn-scale model. The Tsai-Wu failure criterion was employed and the stiffness reduction was conducted in the failed elements according to the different failure modes. The progressive damage process of plain woven SiC/SiC composites under uniaxial tensile load was simulated. The numerical simulation curve is in good agreement with the experimental curve, which demonstrates the predictive capability of the proposed method for predicting the strength of plain woven SiC/SiC composites.