Abstract: The method of strengthening steel structure by welding while under load has been widely used in numerous reinforcement projects． However，despite some general tips，there are no specific provisions in present foreign technical standards． The few specific design provisions are only left within Chinese standards Technical Specification for Strengthening Steel Structures ( CECS 77 ∶ 96 ) and Technical Specification for Inspection，Assessment and Strengthening of Steel Structures ( YB 925796) ． The provisions framework of domestic code and specification to solve the problem of strengthening by welding under load was combed． And the calculation examples and analyses related to design methods of steel columns under axial and eccentric load were given． The concept of joint reinforcement coefficient was also proposed to make unified definition for the unreasonable situation in two standards． By comparison，the discrepancies and inadequacies were pointed out to provide reference for the follow-up researches and code revision．