Abstract: This paper studied the effect of carbon nitride (C₃N₄) on the mechanical and tribological properties of polytetrafluoroethylene (PTFE) by molecular dynamics simulation. Firstly, the amorphous models of pure PTFE and C₃N₄/PTFE composites were established and the mechanical properties were calculated after structural optimization. The simulated results showed that the Young’s modulus and shear modulus of the PTFE were increased by 218% and 141% after C₃N₄ reinforcement, respectively. Secondly, the friction model of PTFE composites sliding against copper was established and simulated under certain load and speed in order to investigate the friction and wear behavior. The simulated results showed that the friction coefficient of pure PTFE was 0.14 and its wear rate was 27.6%, while the friction coefficient of C₃N₄/PTFE composite decreased to 0.11 without obvious wear. Finally, the interaction mechanisms between PTFE composites and copper were revealed by analyzing the variations of relative atomic concentration, atomic velocity, interface temperature, radial distribution function, and binding energy.