Thermal barrier coatings (TBCs) are widely used in the hot end components of advanced aero-engines, effectively prolong the service life of the hot end components, and become essential thermal protection materials for advanced aero-engines. However, in the process of service, some atmospheric sediments CMAS became molten after heating and adsorbed on the surface of the thermal barrier coating, and penetrated into the coating along the defects such as pores and cracks, leading to premature failure of the coating. YSZ thermal barrier coating was prepared by plasma spraying–physical vapor deposition (PS–PVD). XRD, SEM and other characterization methods were used to characterize the phase composition and microstructure of the coating with different corrosion time. The results show that YSZ coatings undergo phase transition after CMAS corrosion at 1250 ℃ . With the increase of corrosion time, CMAS sediments will penetrate into the interior along the columnar crystal gap of the thermal barrier coating, resulting in loose coating structure, columnar crystal fracture phenomenon in the upper region of the ceramic layer, and the coating macro performance is part of the ceramic layer spalling. After 8 h of corrosion, columnar crystals appear in some areas of the ceramic layer and peel off from the bonding layer. The penetration depth of CMAS increases with the increase of corrosion time. The penetration rate of CMAS is relatively fast within 3 h of corrosion, but becomes relatively slow after 3 h of corrosion.