The repair process of traction seat support plate cracking for transportable pressure vessel tank was expounded. According to the documents of transportable pressure vessel tank,the structure and characteristics of the traction seat support plate,the reason of cracking is analyzed and the repair plan is determined. The cracking of traction seat support plate is successfully solved by replacing the same material and thick support plate,adding the pin traction seat support plate,processing proper welding groove,and choosing reasonable welding procedure. And the tank traction support is repaired on time and in good quality,and a good evaluation and effect are gained.