Abstract: Influences of blade non-uniformity on the performance of a centrifugal compressor are studied in this paper with numerical method. Simulation of unsteady flow is performed and FFT analysis of spectrum characteristics of pressure fluctuation at typical locations of vaneless diffuser is carried out. The influences of different blade distribution schemes on the spectrum and acoustic characteristics for vaneless diffuser are investigated. Results show that, with the reasonable blade non-uniformity distribution, the pressure fluctuation can be significantly decreased and acoustics can be restrained while the performances of centrifugal compressor being kept unchanged.