Abstract: A plan is proposed for modification of the new type multi-channel NDT system for steel plate inspection, based on the analysis of the inclusions and lamination defect as existing in the base metal on both sides of the weld seam, including measures like adding integrated probes and properly re-arranging the probe array, etc.After the modification, the detection rate of the system has been remarkably enhanced, owing to the twelve groups of oblique probes that are capable of 100%coverage transversal wave detection to certain area of the steel plate edge, and the two sets of the four-in-one integrated probes that are capable of 100%coverage longitudinal wave detection to the same area of the steel plate.