Abstract: Oscillating experiments were carried out to study the Logarithmic roller on the self-made optical EHL line contact device experiments, which EHL oil film thickness and shape in two different oscillation frequencies were measured. The results demonstrated that contact area film was evenly distributed along the axis within load range. Films were changed under Oscillating motions by extrusion and wedge, were mainly affected by extrusion as entrainment rate was small with low-frequency and mainly affected by wedge as entrainment rate was large with high-frequency. When entrainment rate was zero, film was sealed contact with the region, which became more apparent in high-frequency.