Abstract: The propeller noise in the self noise of ships head sonar position is successfully rejected at above 40 dB by means of the noise cancelling method with revised adaptive lattice filter in this paper.The improved LSL algorithm is characterized by rapid convergence,high accuracy,and wide-band noise rejecfion.The above mentioned noise cancelling system (software) is used to the contribution of each noise source for the self-noise field of sonar position and satisfactery results are abtained on determining main noise source.