Objective To study the factors which influence persistence time of pathologic reflexes and the most sensitive locus that eliciting them.Methods106 patients with first pyramidal tract injured were elicited Babinski sign once a day.The time and locus of hand-motion of examiner,the time and angle of hallux-dorsiflexion,the muscle strength of the patients were recorded.Results and ConclusionThe lower the muscle strength be,the longer the hallux-dorsiflexion persist,the larger the angle of hallux-dorsiflexion be,the nearer the sensitive locus to heel.