The mechanical and tribological properties of CNTs reinforced nitrile butadiene rubber (NBR) composites were studied at molecular level by molecular dynamics simulation.The mechanical properties of materials were calculated by constant strain variation method.Three-layer models of pure NBR and CNTs/NBR composites were established respectively,and shear loads were applied to the iron friction pairs at the top and bottom layers to study the tribological properties of the materials.The results show that in the process of friction,due to the strong adsorption capacity on the surface of CNTs,the migration rate of NBR molecular chain is inhibited,and the interaction between CNTs and polymer molecular chain is enhanced.CNTs/NBR composites have higher density and stronger structure,which shows more excellent mechanical and tribological properties compared with pure NBR.