1. A method for noise reduction, comprising: beamforming audio signals sampled by a microphone array to get a signal with an enhanced target voice; locating a target voice in the audio signal sampled by the microphone array; determining a credibility of the target voice when the target voice is located; weighing a voice presence probability by the credibility; and enhancing the signal with the enhanced target voice according to the weighed voice presence probability; wherein said locating a target voice in the audio signal sampled by the microphone array comprises: computing cross-correlation values of the audio signals sampled by the microphone array; selecting multiple cross-correlation values which are maximum relatively; determining a time difference that the target voice arrives at different microphones of the microphone array corresponding to each cross-correlation value; and determining an incidence angle of the target voice relative to the microphone array based on each time difference.