As the aging of the population continues to deepen, the number of elderly people living alone is also increasing. In the application of solving the problem of elderly living alone, indoor positioning is the most basic and critical issue. Aiming at the needs of indoor positioning, a binocular visual odometer positioning algorithm is proposed, which has been studied from four aspects: Camera imaging model, feature extraction, feature matching and motion estimation. First, the binocular camera is used as the sensor for image acquisition; then the matching relationship between adjacent images is completed by extracting ORB feature points, and the matching relationship between the corresponding feature points of the left and right images is obtained according to the stereo matching algorithm based on the BRIEF descriptor, the camera movement is estimated. The hardware and software platforms are designed to experiment with the proposed method. Experiments have proved that the indoor positioning technology based on visual odometer can accurately locate the position of the elderly indoors, and can safely monitor the elderly in real time.