Abstract: Carbon fiber/vinyl ester resin composite (CF/VE) was gradually applied to large-thickness and large-scale ship structural parts due to its light weight, high strength and corrosion resistance. Due to the limitation of size and manufacturing equipment, the curing of large-thickness composite materials used in ships was often insufficient. In order to understand the durability of incompletely cured CF/VE in hydrothermal environment, the surface morphology change and hydrolysis mechanism of the resin were analyzed, the dynamic mechanical properties and mechanical properties at high temperature of resin and its composites were studied. The results of liquid chromatography-mass spectrometry and FTIR show that the ester bond in the resin molecular chain is strongly hydrolyzed; due to the strong hydrolysis reaction and osmotic cracking of the resin from the surface to the inside, the mass growth rate decreases after reaching the maximum value, and the CF/VE mass is lower than the initial value after 4000 h. The dynamic thermodynamic data shows that the storage modulus and glass transition temperature (T_g) of the resin and CF/VE increase in the early stage of hydrothermal aging, and the thermal expansion coefficient decreases, and the T_g recovers in the later stage of aging. The compressive and interlaminar shear strength of CF/VE at room temperature decreases significantly in the short term of hydrothermal aging, which decreases by 23.0% and 46.6% respectively at 1176 h, and then the performance degradation rate slows down, which decreases by 30.9% and 47.7% respectively at 4080 h. After aging, the tensile and compressive strength of the resin at 70°C increases; and the compressive and in-plane shear strength of CF/VE at 70°C increase.