According to the requirements of modular assembly of large structural modules of AP1000 nuclear power plants, we have independently developed a number of key technologies including a modular assembly platform of large structural modules of AP1000 nuclear power plants, as well as assembly and installation technologies, special tooling and tools, automatic welding technology for S32101 duplex stainless steel, precise orientation and positioning technology for module installation, etc., which have effectively solved the problems of large structural modules, such as complicated positioning environments and high installation accuracy requirements, shortened the construction period, saved the construction cost and ensured the construction quality. This technology has been granted 12 patents (including 4 invention patents), 6 provincial and ministerial science and technology awards and 1 provincial and ministerial normalized construction method.