Abstract: A new generation of domestic T800 grade carbon fiber reinforced high-temperature resistant polyimide resin prepreg was selected to prepare the polyimide composite materials through the hot pressing tank process. Aging treatment of composite materials was carried out using acidic salt spray and humid hot environment to study the changes in typical mechanical properties of the composite materials. In addition, four liquid environments, including the distilled water, aviation fuel, aviation lubricating oil, and artificial seawater, were used to soak the composite material at room temperature for 1000 hours to study the changes in mechanical properties of the composite material at room temperature and 280 ℃ before and after soaking respectively. The results showed that the effect of acid salt spray treatment on the layer shear performance reached 13.4% and the damage to other mechanical properties is within 5%. The humid and hot environment treatment causes no obvious damage to mechanical properties. After four kinds of liquid environment immersion, the distilled water and artificial seawater immersion caused slight damage to the shear performance of the normal temperature layer, and the performance decreased by about 7%. The high temperature in-plane shear performance damage is not obvious. The damage of shear performance between normal temperature layers is small, less than 5%, the damage of shear performance between high temperature layers is increased, and the damage of distilled water and artificial seawater reaches 10%. The damage of open compression at room temperature is less than 3% and the damage of high temperature open compression is increased, and the damage of distilled water, jet fuel and artificial seawater exceeds 10%.