Abstract: This paper reviews the development history, signal mechanisms, and typical waveform characteristics of Ballistocardiography (BCG) as a physiological monitoring technology. It also summarizes signal processing techniques, including preprocessing, feature extraction, and deep learning. Drawing on the latest research, the paper discusses current applications in cardiovascular monitoring, sleep and respiration analysis, and exercise assessment. Furthermore, it addresses key challenges related to cross-device consistency and explores future directions for the development of BCG technology, offering a comprehensive reference for its research and application.