Abstract: Spherical tank manufacturing commonly faces problems such as forming deviation of spherical shell plates, difficulties in on-site assembly adjustment and poor control of welding deformation. From the perspective of lean manufacturing, this paper establishes a framework for the virtual assembly of spherical tanks. Based on laser scanning inspection, reverse modeling and simulation technologies, digital twin verification between physical components and digital models is realized throughout physical data acquisition, virtual analysis, welding simulation and construction guidance. It enables full-process quantitative analysis for spherical tank production, ranging from forming inspection of spherical shell plates to on-site installation. Practical application results show that this technology can effectively improve the forming quality of spherical shell plates, shorten the assembly cycle and reduce rework losses, which fully demonstrates the application value of virtual assembly technology in the lean manufacturing of spherical tanks.