Abstract: Briefed are the demagnetization theory and the demagnetization processes as commonly used for SAWH pipes. Focused on is the homogeneous magnetization-based infinite DC on-line 2-point demagnetization process for SAWH pipes,which involves setting up the No.1 demagnetization point at the outlet table of the SAWH pipe mill proper,and the No.2 demagnetization point in the X-ray detection room. In case of using this demagnetization process, the demagnetization field size is accurately identified and adjusted via the picture of the X-ray industrial TV, and thus adequate demagnetization of the SAWH pipe is obtained,and rebounding of remanent magnetization is prevented. And in this way,satisfactory demagnetization is realized by means of simplified equipment and fine control process.