Abstract: A signal processing approach combining pre-processing,variational mode analysis,and partial coherence analysis is employed to analyze acoustic noise measurement data in a fuel cell system under different operating conditions.Coupling with the analysis of components behaviors in the fuel cell system,the main noise sources,characteristic frequencies and their contributions are identified at each working condition.Under low-load power output condition,the dominant noise source is the hydrogen recirculation pump and water pump with characteristic frequencies of 200 and 1280 Hz,and contributions of 0.42 and 0.77,respectively.Under highload power output condition,the main noise source switches to the air compressor with characteristic frequency of 8920 Hz and contribution of 0.24.The fuel cell system noise characteristics is obtained in this study under different working conditions.The analysis method proposed in this study can be used for evaluating noise characteristic of fuel cell systems tested in non-anechoic chamber.