Discrete noise source suppression in underwa-ter acoustic channel has attracted great attention in recent years. The paper proposes a new principle for dealing with the problem. This new principle is called matched field noise suppression (MFNS). Based on a previous work of the au-thors group, a full understanding about how a discrete noise source shows effects on the performance of a towed hydro-phone line array has been obtained. In light of that finding, MFNS is proposed, which explores and utilizes the charac-teristics of the noise transmission channel to achieve much greater suppression of the noise in comparison with existing approaches. MFNS combines the concept of matched field processing (MFP) and optimal sensor array processing (OSAP) together to suppress the discrete noise source and to maintain an optimal beam for receiving far-field wanted plane wave signals. A MFNS beam-former is deduced in constraint with signal plane-wave response being unit and noise matched field response being zero. A closed-form solution of the weight vec-tor for the beam-former is given. Computer simulation results agree well to the theoretical analysis. The new principle is called matched field noise suppression (MFNS). Based on a previous work of the au-thors group, a full understanding about how a discrete noise source shows effects on the performance of a towed hydro-phone line array has been. In light of that finding, MFNS is proposed, which explores and utilizes the charac-teristics of the noise transmission channel to achieve much greater suppression of the noise in comparison with prior approaches. MFNS combines the concept of matched field processing (MFP) and optimal sensor array processing (OSAP) together to suppress the discrete noise source and maintain an optimal beam for receiving far-field wanted plane wave signals. A MFNS beam-former is deduced in constraint with signal plane-wave response being unit and noise matched field resp onse being zero. A closed-form solution of the weight vec-tor for the beam-former is given. Computer simulation results agree well to the theoretical analysis.