###### Abstract  
The current status of the research of _Ballistocardiography_ (BCG) and _Seismocardiogram_ (SCG) in the field of medical treatment, health care and nursing was analyzed systematically, and the important direction in the research was explored, to provide reference for the relevant researches. This study, based on two large databases, CNKI and PubMed, used the bibliometric analysis method to review the existing documents in the past 20 years, and made analyses on the literature of BCG and SCG for their annual changes, main countries/regions, types of research, frequently-used subject words, and important research subjects. The results show that the developed countries have taken a leading position in the researches in this field, and have made breakthroughs in some subjects, but their research results have been mainly gained in the area of research and development of the technologies, and very few have been actually industrialized into commodities. This means that in the future the researchers should focus on the transformation of BCG and SCG technologies into commercialized products, and set up quantitative health assessment models, so as to become the daily tools for people to monitor their health status and manage their own health, and as the main approaches of improving the quality of life and preventing diseases for individuals. Ballistocardiography; Seismocardiogram; medical care and nursing; health management and nursing; technical practice 2021 16 September 2021 2021 16 September 2021 of heart activities [2; 3]. Its earliest discovery dated back to 1877, when [PERSON] et al. [4] observed the phenomenon of BCG signals, i.e., when a human body stood on a scale, the scale pointer swung regularly in synchronization with the heartbeat. This was the earliest BCG record. Then, in 1939, [PERSON] et al. [5] were the first to systematically study body trembling caused by heart contraction. They also designed and made a platform capable of recording body movement, and systematically studied the relationship between the formation mechanism of various waveforms in BCG signals and the heart dynamics, thus laid the foundation for researching the subject of BCG [3; 6]. Thereafter, during the period of 1940 to 1980, the academic circles proposed various methods for detection of BCG signals, to apply BCG technology to clinical medicine for research of various physiological parameter detection [6; 7; 8]. The expression of its typical waveforms is shown in Figure 1. The significant morphological features of its output can be used to analyze human health information [9; 10]. For example, the amplitude of I] segment reflects fluctuation of cardiac output (CO), associated with difference in aortic blood pressure [11]; and peak J, the highest peak, corresponds to the movement of ventricular valves and can be used for monitoring to predict cardiac function [12]. Figure 1 shows _Electrocardiogram_ (ECG), _Ballistocardiogram_ (BCG), and tri-axial _Seismocardiogram_ (SCG) in a human volunteer [13]. For the SCG, the x, y, and z subscripts correspond to the medial-lateral, the cranialcaudal, and the posterior-anterior axes respectively. The S1 and S2 components, and their respective fiducial markers are shown labelled: MC = mitral valve closure, AO = aortic valve opening, RE = rapid ejection, AC = Aortic valve closing, MO = mitral valve opening and RF = rapid filling. But after the 1980s, the research of BCG was gradually stopped [6; 14] for the reasons of its bulky equipment and complicated signal analysis, which caused the researchers to turn their sight to electrocardiograph (ECG) shows as Figure 1. ECG is a graphical representation of heart voltage over time measured by electrodes placed on the skin. It is a standard non-invasive diagnostic and monitoring technique used to record far-field cardiac electrophysiological signals. During normal sinus rhythm (NSR), the ECG will produce a stable and reproducible waveform of healthy subjects. This waveform is used here to  
Figure 1: ECG/BCG/SCG signals.