Abstract: High-speed train brake pads are the core components for the safe operation of high-speed trains, and their performance directly affects the braking effect and safety of the train. Copper-based powder metallurgy friction materials have gradually become an important material choice for high-speed train brake pads due to their excellent mechanical properties, wear resistance, and thermal conductivity. Particle-reinforced copper-based friction materials have excellent friction and wear properties, which can meet the application requirements of engineering materials in high-strength and complex environments and have broad application prospects. However, the second phase and the matrix are prone to interface reactions, causing lattice distortion, which affects the interface relationship, mechanical properties, and wettability of the matrix. These problems not only reduce the safety and reliability of high-speed train brake pads but also pose more severe challenges to the service life and maintenance costs of the materials. The influence of intermetallic compounds, metals and alloys, carbon materials and ceramic materials on the microstructure, structure, and friction and wear properties of copper-based friction materials was mainly discussed. Some existing problems of copper-based friction materials were pointed out, and the future development trends of the reinforcing phase were prospected.