Abstract: Base on the comparative investigation of the friction behavior of nature articular cartilage using two lubricants, the effect factors on the cartilage friction were discussed. Contact deformation and coefficient of friction between bovine knee cartilage pairs were measured on two kinds of saline solution and 50% bovine serum using UMT-2 Multi2 specimen test system. Contact angles of two lubricants on the cartilage surface were also obtained. These results show that contact deformation was made up of cartilage deformation and wavy deformation. Cartilage deformation functioned as a nonlinear relation with time while wavy deformation as a nonlinearly periodic relation with time. Surface profiles of the cartilage samples played an obvious role on the wavy deformation and coefficient of friction. Contact angle of saline solution was lower than that of bovine serum while cartilage deformation and coefficient of friction based on the lubricant of the saline solution were higher than those of bovine serum. These differences between tow lubricants may be caused by boundary lubrication.