Abstract: In order to study the feasibility of 12 Cr1 MoV within 8 mm without post-welding heat treatment, the welding procedure tests were carried out through three welding methods of hot wire TIG, manual TIG and shielded metal arc welding. The mechanical properties, metallographic structure, welding residual stress and durability of the joint were studied and analyzed. The results showed that the 12 Cr1 MoV welded joints with wall thickness no more than 8 mm could be welded by TIG and low hydrogen shielded metal arc welding without post-weld heat treatment. Through the comparative test, it was proved that it was not necessary to adopt measures of preheating before welding and slow cooling after welding when the post-welding heat treatment of joints with thickness of 8 mm or less was cancelled.