To effectively reduce the noise of the fuel cell centrifugal air compressor system, a perforated muffler capable of broadband noise reduction was designed. Using the method of computational fluid dynamics coupled with computational aerodynamic acoustics, the noise reduction effect of the perforated muffler was analyzed under different operating conditions of the compressor. Additionally, the thermoacoustic transformation relationship inside the muffler was quantified. The results show that the cavity thickness and perforation rate of the perforated muffler play a decisive role in absorbing highfrequency sound wave components. Compared with the lowfrequency sound waves, the perforated muffler is more effective at attenuating highfrequency sound wave components. As the rotational speed increases, the muffling effect on the highfrequency components gradually enhances, while the effect on the lowfrequency components remains almost unchanged. The thermalacoustic conversion analysis of the perforated muffler shows that under lowspeed operation conditions, the energy of acoustic oscillation before and after muffling is almost completely converted into the exergy of the air. In contrast, under medium and highspeed operating conditions, the proportion of acoustic oscillation energy converted into air exergy is relatively small. To design a muffler that can achieve broadband noise reduction under various operating conditions, the attenuation of lowfrequency sound waves at high rotational speeds should be the primary optimization target. The improvement of thermodynamic performance before and after muffling at low rotational speeds should also be considered. The work presented in this paper provides a new method for reducing the aerodynamic noise of centrifugal air compressors, and offers a theoretical basis for designing highefficiency air compressor mufflers with wide working condition adaptability.