Abnormal foot movements seen in hemiplegic patients include drop foot and clubfoot. This study aimed to detect and evaluate abnormal foot movements during early stance phase of hemiplegic patients using inertial sensors. Two inclination angles associated with abnormal foot movement were calculated from acceleration and angular velocity obtained from inertial sensors, and reference range of healthy subjects was created by defining a two-dimensional plane with these two angles. In addition, the angle distribution was divided into 3 groups based on the stride length, and the reference range was created for each group. Measured data of paralyzed side of a hemiplegic subject was suggested to be abnormal foot movements by comparing to the reference range. Therefore, the reference ranges of healthy subject for different stride lengths are expected to be useful for the detection and evaluation of abnormal movements of hemiplegic subjects.