Counties play a key role in the process of China's economic development. They are also the main front for the implementation of rural digitalization. Digitalization of rural area is also an important driving force to promote the development of county economy and to increase farmers’ income. There are many problems in the construction of county-level digitalization in China, including the inferior infrastructure, the uneven development between countryside and city, the lack of operational and data-share mechanism, as well as the shortage of funds and qualified personnel. Agricultural and rural big data along with big data platform are the foundation of developing digital countryside, as well as the key aspect of top-level design of rural digitalization. Under these background, this paper proposes a “5+N+N” framework to implement county-level rural digitalization, i.e., establishing a rural big data resource catalog, performing a comprehensive evaluation of rural digitalization development, formulating a master plan as the guidance of the implementation of rural digitalization, setting up an integrated service rural digital platform, constructing a digital agriculture demonstration area (and model villages or towns for digital rural governance), and promoting multi-scenarios for the application of digital technologies, and implement several back-up projects. Through the cooperation of governments, enterprises and research institutions, the intercommunication among the digital economy management platforms of the country, province and city levels, and the applications of the towns and villages will be connected, and the overall promotion of county-level rural digitalization will be achieved. This framework provides a pathway to the top-level design for the development of digitalization in counties, which could help county governments set implementation plans for local rural digitalization process, and promote digital transformation of county economy.