The characteristics of zeroentrainment elastohydrodynamic lubrication of roller friction pairs were studied under the swing conditions on the optical line contact EHL experimental device.The variation of film thickness of roller at the zeroentrainment was investigated under the same load in different cycle,and the influence of load on the characteristics of zeroentrainment elastohydrodynamic lubrication of roller was analyzed.The results show that when the roller speed is close to zeroentrainment,the extrusion effect plays a dominant role,the oil film is sealed within the contact area to form depression,and the oil film is thinner.In the reciprocating motion,the number of roller periodic motion influences the oil film thickness of roller at the zeroentrainment,the oil film thickness in the middle of the roller is minimum at the start moment of roller,and it is increased gradually with the increasing of the swing frequency,and then reaches a relatively stable state after swing for many times.Load has a large influence on the EHL characteristics of roller at the zeroentrainment,with the increasing of load,the contact area is increased,the minimum film thickness in the roller end is decreased,and the edge effect of roller end is increased.