Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology. It is beneficial to improving the safety of human beings while walking on a ramp. Based on the trajectory of mass center of body (MCOB) and the mechanical analysis of human body while walking, conclusion could be drawn that the required step frictional coefficient (RSFC) exhibited an M shaped curve during the foot contacting with the ground and got its maximum and minimum values when MCOB of the subject was at the highest and lowest position respectively. Moreover, the first peak of RSFC decreases firstly and then increases, while the second peak of RSFC increases with the increase of slope inclination at the experimental condition. The position of pivotal point is decided by the relative size of slope inclination and the angle between the plumb line through MCOB and the line from foot to MCOB.