Abstract: X-ray digital radiography examination is a new technology of non-destructive testing(NDT), and GB 17925—1999 Standard Practice for X-ray Real-time Examination of Cylinders Weld is the national standard for the cylinder industry with more than ten years successful application. On the basis of the passed experiences, the revision of GB/T 17925—2011 Standard Practice for X-ray Digital Radiography Examination of Cylinders Weld was issued, which a lot of new content was added. The revise of image, storage and transmission in the standard was guided with our System Control Theory so that the standard was more with strong clarity, completeness and operability.