Abstract: The polyurethane pipe of a robot equipment cracked. The cracking reason was analyzed by macroscopic observation, infrared spectrum analysis, mechanical property test, scanning electron microscope and energy spectrum analysis. The results showed that the polyurethane pipe did not undergo thermal oxidative aging and ultraviolet aging. The fine aluminum particles in the environment caused wear on the surface of the pipe, and the damage became a stress concentration point and cracks were initiated. The cracks further expanded and penetrated the wall, eventually led to internal medium leakage.