The purpose of this study was to analyze of the rider postural alignments according to the fitting of stirrups lengths during walk of high level riders. Participants selected as subject were consisted of horse riders of high level (age: 47.66±3.51 yrs, height: 168.40±4.84 cm, body weight: 73.36±15.58 kg, low extremity length: 94.76±3.98 cm, career: 23.33±5.77 yrs) and walk with 3 types of stirrup lengths(ratio of low extremity 68.04%, 73.25%, 78.48%). The variables analyzed were consisted of the displacement of Y axis (center of mass, head, thigh, shank and foot), FR angle, LR angle, dynamic postural stability index (DPSI), coefficient of variation (CV%), and distance (X axis) of low extremity limb between right and left. The displacement of Y axis in COM, thigh, shank, foot limbs were not statistically significant, but movements of head showed greater distance of B type and C type than that of A type during 1 stride of walk. The FR and LR angle in trunk of horse rider, dynamic postural stability index and, coefficient of variation didn`t show significant difference statistically according to the fitting of stirrup lengths. Also the distance (X axis) of low extremity in thigh and shank didn`t show significant difference statistically in between right and left, but right and left foot showed greater distance in C type than that of B and A types during walk in horse back riding. The hip and ankle joint angle not statistically significant according to stirrups lengths, But knee joint angle showed more extended according to the increase of stirrups lengths during stance and swing phase in walk.