The aimed environmental barrier coatings (EBCs) need to meet the characteristics of low oxygen permeability, match thermal expansion coefficient, and keep phase stability under service conditions, which usually need to be designed as a multi-layer structures to avoid premature failure of gas turbine engines during operation. Yb2Si2O7 (YbDS) is considered the most promising candidate due to its excellent resistance to water vapor corrosion and damage tolerance, a similar coefficient of thermal expansion(4.1×10–6/K) to that of the matrix material (SiC, 4.7×10–6/K), and does not generate high thermal cycling stress in EBCs systems. However, when YbDS was exposed to an environment containing with high-temperature water vapor, corrosion transformation may occur, which would reduce the durability of EBCs. To analyze the corrosion process, stress characteristics, and crack propagation laws of YbDS under the coupling effect of water-oxygen corrosion and thermal cycling, the compositional and structural changes of YbDS under high-temperature water-oxygen action were determined through experiments, also the influence of water–oxygen corrosion on the stress evolution of the coating was explored using finite element software Abaqus. The extended Finite Element Method (XFEM) was used to simulate the propagation path of cracks in YbDS, and the accelerating effect of water–oxygen corrosion on crack propagation was discussed finally.