Acupuncture's mechanism keeps unclear especially from biomechanical perspective though its effect on knee osteoarthritis (KOA) has been proved. Seventeen KOA cases in electro-acupuncture (EA) group and 18 cases in minimal acupuncture (MA) have done gait analysis motion analysis during stair climbing before and after EA or MA treatment. (1) Less pain and higher velocity of stairs descending ( P < 0.05) after EA treatment. (2) Second peak knee adduction angle (PKAA2) increased after EA treatment ( P < 0.05). (3) At first peak external knee adduction moment (PEKAM1) event after EA, knee adduction angle, vertical (Z-axis) ground reaction force (GRFZ), knee extensor torque and ankle eversor torque increased; hip external rotation angle decreased ( P < 0.05 or P < 0.01). Same event after MA treatment, hip external rotation angle, lateral (X-axis) ground reaction force (GFRX), hip extensor and ankle internal rotators torque became lower ( P < 0.05 or P < 0.01). (4) At PEKAM2 event after EA treatment, knee adduction angle increased; hip adductor, hip extensor and hip internal rotators torque decreased ( P < 0.05 or P < 0.01). Same event after MA treatment, GRFX was higher; hip flexion angle, ankle internal rotator, hip extensor and hip internal rotator torque was lower ( P < 0.05 or P < 0.01). (5) Hip flexion angle was smaller in EA than in MA at PEKAM2 and PKKAA2 events. Ankle eversor torque was higher in EA group than in MA group at PKKAA1 event ( P < 0.05 or P < 0.01). EA increased velocity of descending stairs, may improve loading capacity in hip, knee and ankle joints, indicating less compensatory strategy of lower limbs with less pain. MA showed different effect.