Abstract: This paper presents the theoretical analysis of the imaging method and characteristics of the Near-field Acoustical Holography (NAH).Aiming to the unstability of the source reconstruction,we present a new filtering method————least squares method for filtering with restraint,which improves the stability of the reconstruction.The computer simulant experiment for the vibration and radiation of a round plate by means of the numerical method of NAH has been done and the effect of the new filtering method has been tested.The NAH imaging research of the radiation of a small loudspeaker using a scanning linear receiving array of 32 elements has been made and the preliminary results are also given in the paper.