Boiler X-ray inspection is based on the difference in the absorption of X-rays by different material thicknesses. The X-ray inspection of boiler is to show the internal defects of materials, parts and welds from the film and image by using the X-ray perspective photography and real-time imaging of industrial television. Such as crack, shrinkage cavity, air hole, slag inclusion, undissolved, incomplete penetration and etc. The quality of materials or products can be evaluated by observing the nature, size and position of defects, so as to prevent major accidents caused by internal defects and poor processing of materials.