Abstract: A new method of defect detection X-ray images of weld using optimized heuristic search based on image information fusion was introduced.In order to achieve real-time defects detection, weld segmentation using wave analysis was performed just after the pre-processing of the image, then image information fusion technology was used to set up searching base with revelatory knowledge, finally heuristic search was used to locate all the pixels in defects and the pixels were grouped by adjacency characteristic.Each group of pixels corresponds to certain defect in the weld.Experiments show that the mentioned algorithm can detect defects in X-ray images of the weld with great efficiency and reliability.The algorithm can be used for industrial applications of real-time weld defects detection in X-ray non destructive testing.