The research objective includes detailing of the essence and structural changes of the digital economy (DE) at the national level; an explanation of the features of digital innovations; the role substantiation of diffusion of innovations (DI) as a key driver for DE development. The research methodology is based on: structural, institutional, historical, comparative, functional analysis, formalization method. The need to achieve all-encompassing digitalization nature and the systematic use of digital technologies, as well as the transition to digital models of organization through the diffusion of technologies, is taken into account. The research results are the detailing of the essence and structural features of DE. DE is considered as a new type of economy, characterized by the widespread adoption of digital technologies, cyber-physical systems, intelligent solutions, network technologies. The DE nature is revealed from the position of several approaches: technological; structural; component-resource; functional. The DE features (network nature, a new type of entrepreneurship, a new class of specialists, new institutions, etc.) are highlighted, as well as the negative consequences of the transition to such an economy; overcoming of these negative consequences requires smart policy with a focus on productivity growth, structural changes and growth incentives. The DE structure, including parts of the Internet economy (e-Commerce, e-Health, e-Education, e-Banking, etc.) and new forms of providing various services, is characterized. The IT sector growth is indicated as the DE “core”, where new jobs, infrastructure, cost are created, and the technology business is developed. The structural proportions of DE are largely determined by technological trends (on-demand economy, sharing economy, Internet of Things, etc.). Digital platforms as new intermediary mechanisms, as well as the Big Data market, are one of the key structural components of DE. The subject and features of digital innovations are highlighted. On this basis, the DI role in the DE development is substantiated, taking into account the provision of all-encompassing digitalization nature, stimulation of innovations, ensuring the benefits and economic growth, as well as the creation of economies of scale, chain and cumulative effects. Practical recommendations on the intensification of DI processes in the context of DE building include: targeted government support that concerns the IT and other sectors; establishment of technology transfer and commercialization centers, technology platforms and technology leadership programs; quality improvement of education and training; infrastructure role expanding of universities; development of research, innovation, entrepreneurial networks, professional communities, industry associations. In this context, it is necessary to strengthen support for small and medium-sized innovative businesses that should become a provider of new technologies. It is advisable to create portals for oriented R&D and adoption of technologies; knowledge management platforms during technology transfer process; industry knowledge bases; portals for experts work activity management for project evaluation. Value/originality. The article details the essence and reveals the structural features of DE, describes the specifics of digital innovations, as well as presents DI as a key driver for the development of such an economy.