The invention provides a method and device for establishing a feature library based on gait recognition and face recognition, and the method comprises the steps of firstly obtaining a monitoring video, and screening out a monitoring image of each pedestrian feature from the monitoring video, secondly, extracting the face features of the pedestrians, and determining the occurrence time of the monitoring images of the pedestrian features in the monitoring video, determining a gait feature video which contains the monitoring image in the monitoring video and has a video duration of a preset timeperiod through the occurrence time of the monitoring image in the monitoring video and a preset time period, and extracting the gait features of pedestrians in the gait feature video, and finally, establishing the feature library according to the face features of each pedestrian and the gait features corresponding to the face features of each pedestrian, so that the accuracy during the identity recognition process is improved.