The work aims to investigate the effects of liquid/solid interface on thickness of hydrodynamic lubricating film. In an optical surface-contact lubricating film thickness tester, the surface-contact friction pair was composed of a rotary optical glass disc and a stationary micro slider. PAO6 and 80% glycerol aqueous solution were used as lubricants while steel and SiO2 were used as the surface materials of sliders. In the test, one lubricant was combined with different surface materials of sliders and different lubricants were combined with one surface material of sliders to constitute different interface groups. For each interface group, film thickness-speed curves were measured under different conditions. The affinity of various interfaces was assessed by the liquid-solid contact angles. Results indicated that the PAO6/steel interface and the PAO6/SiO2 interface showed negligible difference in film thickness-speed curves, and the curves agreed well with theoretical predictions. The contact angle of PAO6 on these two slider surfaces were 17.5° and 21.9° respectively, showing strong affinity but less difference between the two. However, in case of large affinity difference in the interface groups, the film thickness also showed difference. When the interface affinity was weak, or corresponding liquid-solid contact angle was large, the film thickness was relatively low. Under the present experimental conditions, interfacial effects varied significantly with the increase of load. Preliminary analysis indicated that load increase would induce slippage and therefore enhance interfacial effects since it would increase shear rate of oil film at the outlet of friction pair. Provided with hydrodynamic lubrication, the affinity of solid/liquid interface can have obvious influence on the film thickness.