Heavy launch is the key to the future realization of manned lunar landing,space station construction and deep space exploration. This paper introduces the design structure of the mainstream rocket connecting ring at home and abroad,and uses the three configurations of the forked ring,Y ring and flanging T ring as the design input of the future heavy rocket connecting ring,the influence of different connecting ring structures on the assembly welding of the heavy launch body is analyzed in detail from the aspects of process flow,tooling design and welding technology. It is pointed out that the limitations and advantages of the connecting ring and the short shell,and provides reference for the design and development of heavy vehicle rocket body structure.