Abstract: Natural gait planning is a feasible method for energy optimization and gait compliance of humanoid robots;it demands quantitative analysis on the human locomotion and its balance strategy.Consequently the principle of natural gait planning is analyzed.An effectual experimental testing system is proposed and a parametric database of human gaits is constructed via experiments.The experimental result reveals the parametric characteristics of human gaits and its balance strategies which offer theoretical references for natural gait planning and control for humanoid robots.The conclusion specially indicates that the successful natural gait for humanoid robots can not be achieved only by planning,viz.,the planning should be combined with the bionic control strategy.In addition,the experimental results are good references for design optimization of humanoid robot prototypes.