A sound processing device is provided. The sound processing device includes a microphone array and a post filtering module. The microphone array includes microphones aiming to different directions and configured for receiving sound signals. The post filtering module is configured for receiving the sound signals from the microphone array, filtering the sound signals to generate groups of filtered signals each corresponding to one of the sound signals, wherein each of the filtered signals within a group corresponds to one of different frequency bands, generating band signals each based on a comparison of an intensity of one of the filtered signals that corresponds to the same one of the frequency bands in each group of the filtered signals and a noise intensity correlation between the frequency bands and adding the band signals to generate an output sound signal.