Abstract: For the long range performance of towed linear array sonar and its requirement about restraining rehicle noise,the problem that several strong interferences in all the bearing should be suppressed is raised.When strong interferances have wideband and deviate from signal direction,the performance of adaptive interference canceller is limited by a large Fractional Dispersion.This paper discusses the perpormance of a partially adaptive sidelobe canceller which is used to suppress,wideband and large bearing interference in towed linear array sonar.The results of numerical method state that the partially adaptive sidelobe canceller provided witheproper parameter and construction has good cancelling performance for interference with suitable band and bearing.