Abstract: A sitting and standing dual-purpose ballistocardiography (BCG) signal detecting system was put forward and implemented. The high-precision A/D converter chip TM7708, the program-controlled scaling amplification technology and the digital filtering technology to detect BCG signals were adopted in the system. By using wavelet analysis for the noise elimination, the characteristic waveform was extracted, and at last, the heart rate can be detected automatically through VB software programming. The system was tested by using 30 healthy people as samples. These BCG signals were compared with the single-channel electrocardiosignal acquired synchronously. The results showed that the two kinds of signals were synchronous. The accuracy of the heart rate detection was about 98.2%. It verifies the feasibility of the developed system. The portable system can automatically detect the BCG signals of the subjects at any time, which will provide a reference for the extraction and analysis of heart and respiratory signals.