The timebased static immersion tests of the prepared nitrile rubber(NBR) samples with different acrylonitrile content were carried out.The unidirectional sliding wear tests of the NBR samples before and after swollen were performed by the MPV600 ringonblock wear tester under dry friction conditions.The wear surface morphologies of the NBR samples before and after swollen were analyzed,and the effect of swelling on wear behavior of NBR samples under dry friction conditions was discussed.The results show that the wear loss of the NBR samples is increased after the swelling tests,and the swelling influence degree is increased with the increase of swelling time,and decreased with the increase of the acrylonitrile content.After swelling,the soften phenomenon of the NBR samples under the action of friction heat intensified,and the wear form changes from shear tear to adhesive wear with the increase of the swelling time.The easier cutting effect time and the degree of adhesion are decreased with the increase of acrylonitrile content.A large number of holes can be clearly seen on the wear surface of the swollen samples and the rubber material is visible on the friction wheel surface of the grinding pair,and the adhesion area of the rubber material on the surface of friction wheel is increased when rubbing with swollen samples.