During the use of the laser melting system,the powder feeding nozzle is easily to be worn by the powder flow under high temperature environment.However,the damage mechanism of the nozzle is still unclear due to the complex equipment structure and numerous influencing factors.The wear law and high temperature damage mechanism of nozzle were studied by the case analysis as well as simulation frictional experiment,combined with scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).The results show that the outlet of the powder feeding nozzle is closer to the high temperature source,resulting in more severe wear than other areas,and the wear form is from slight fatigue wear and abrasive wear caused by mechanical stress to severe tribochemical wear dominated by tribochemistry.Under the coupling action of temperature-stress multi-physical field,the nozzle material undergoes serious oxidation reaction,leading to the interface porosity to be easily removed.In addition,brittle titanium-copper intermetallic compounds may be formed at the friction interface,which is one of the main reasons that cause the nozzle outlet to be easily worn.The research results provide theoretical support for the design and application of powder feeding nozzle at high temperature.