The invention relates to a method for determining abnormal gait comprising the following steps: (a) measuring ground reaction force generated during walking by a plurality of sensors arranged on the left-foot and the right-foot respectively (b) applying measurements from each of the plurality of sensors to a predetermined fuzzy membership function to transform the measurements into the first fuzzy values (c) applying the first fuzzy values to a predetermined fuzzy logic to generate the second fuzzy values for a plurality of gait phases and (d) comparing the second fuzzy values with pre-stored data of normal gait to determine whether it is abnormal gait or not. Therefore, it is possible to determine abnormal gait more accurately even with fewer sensors.
