A gait analysis method is implemented by a gait analysis system including a sensing unit, a storing unit storing a plurality of computing programs, and a processing unit electrically connected to the sensing unit and the storing unit, and comprises steps of: sensing a gait by the sensing unit to output a sensing signal, wherein a gait cycle includes a stance phase, a push-off phase, a swing phase and a heel-strike phase obtaining a signal vector magnitude (SVM) and a signal magnitude subtraction (SMS) by the processing unit according to the sensing signal identifying the stance phase, push-off phase, swing phase and heel-strike phase according to the SVM and SMS, wherein the push-off phase, swing phase and heel-strike phase are determined according to a dynamic threshold and implementing a classification of the gait according to the stance phase, push-off phase, swing phase and heel-strike phase.
