In this paper, a new technique about long distance source localization with active and passive towed line array is presented. At first, a acoustic scattering field receiving equation for active and passive line array is derived. Then, this new method is described in detail that obtains a long distant azimuth, range and depth source localization by the normal-mode filter and the large synthetic aperture through horizontal moving of a short line array. The simulated results indicate that the estimation of accuracy in azimuth and range source localization is improved by this method. In addition, it is certificated that the active and passive line array can realize effectively long distant source localization by normal-mode filtering method.