In view of the different characteristics of the frequency response of different audio playback devices, the Equalizer algorithm for audio frequency equalization adjustment and noise elimination is designed and implemented on the DSP. Based on the principle of time-domain filtering in digital signal processing, the IIR low-pass and high-pass filters that can pass through different frequency bands is designed. Different frequency bands are set with different gains. The output signal after the input audio passes through the IIR filter is superimposed to realize the audio regulating effect of energy changesat different frequencies; at the same time, the separate and controllable noise suppressor is designed, which is composed of a 50-order FIR band-stop filter for noise attenuation at a specified frequency. The test shows that the 16Bit digital audio signalup to 16KHz can be processed, and the filtering of noise in a specific frequency band is achieved.