Abstract: Thermal aging significantly affects the mechanical properties of high-performance composites. In this study, short carbon fiber-reinforced polyetheretherketone composite cylindrical tubes (CF/PEEK) and short glass fiber-reinforced polyetheretherketone composite cylindrical tubes (GF/PEEK) were subjected to thermal aging treatment at various elevated temperatures for 100 h. Subsequently, quasi-static compression tests and Split Hopkinson Pressure Bar (SHPB) impact tests were conducted, and the evolution mechanisms of thermal aging on the material microstructure were investigated via Scanning Electron Microscopy (SEM) observations. The results indicate that CF/PEEK cylindrical tubes exhibit superior microstructural stability compared to GF/PEEK tubes after aging; furthermore, the yield strength of both types of cylindrical tubes increases with rising thermal aging temperature. These findings provide a scientific foundation for structural optimization and reliability design of PEEK-based composites under long-term high-temperature service conditions.