Synthetic heart sound signals have certain application value in the teaching and scientific research. Here, a composite heart sound generator is designed. Firstly, the generation mechanism and chaos characteristics of heart sounds are analyzed, and the principle of composite heart sound is composed. Then based on chaotic characteristics of heart sound, a heart sound generator is constructed, which includes heart sound generating sub model on the left and right. With that, a set of amplitude and period adjustable synthetic heart sound signal is obtained by processing the output waveform. After the analysis of time-frequency and chaos characteristics of synthetic heart sound signal, it reveals that synthetic heart sound signal is highly similar to actual heart sound, and it can basically meet the need of teaching and scientific research.