Abstract: Emerging and re-emerging infectious diseases have become major global public health concern. Due to busy transportation and increased population movement, the core megacities in China have higher risks of international importationand subsequent local transmission of the diseases, but tailored technical support tool systems are limited. Based on the analyses on the international toolkit development and current status of infectious disease prevention and control in China, a development framework for a key technical toolkit for the risk assessment and prevention of local transmission of importedemerging and re-emerging infectious diseases in core megacities is suggested. With the full-chain prevention and control process of "surveillance-assessment-response-public health education" as the main thread, the toolkit is driven by artificial intelligence technology and underpinned by a specialized basic knowledge base, adopting an overall architecture of "1 basic module + 3 functional modules". The basic module is the infectious disease basic knowledge base, which provides authoritative knowledge support. The three functional modules are for domestic and international imported infectious disease surveillance and identification, the risk assessment of importation and local transmission, and local transmission response. The toolkit takes digital platform as core carrier, supports multi-terminal access and cross-system data integration, and the evaluation of the toolkit was based on a combined approach of retrospective case validation and multi-stakeholder questionnaire survey. This study can provide a reference for toolkit development, improve risk identification and transmission response, reduce the workload of frontline prevention and control forces, and the development of technical solutions for core megacities and other cities in China.