Abstract: In this paper,we propose a design of a new wideband spectrum analyzer based on polyphase filters.An input wideband radio signal is processed successively by polyphase filters and a power detector,then the output is integrated under a controlled time to finally yield the measurements of the spectral intensities.Simulations show that this design is rather effective.With polyphase filters the data processing amount decreases greatly,which allows overcoming the disadvantages of a traditional method and achieving wideband spectrum analysis in real time.