Scientific understanding of the relationship between digital economy and urban-rural gap is of great significance for the realization of urban-rural integration. From the perspective of digital economy, this paper expounds that the digital economy takes digital knowledge and information as the main production factors, takes modern information network platform as the main way, and relies on digital industrialization and industrial digitization to form business innovation and mode innovation, so as to achieve efficiency improvement and economic structure reorganization, and act on the change law of urban-rural gap. This paper measures the level of digital economy from the two dimensions of Internet economy and digital finance, and uses the principal component analysis method to construct the urban-rural gap index from the three dimensions of urban-rural income gap, consumption gap and consumption structure gap. Based on the panel data of 30 provinces in China from 2011 to 2021, taking full account of the spatial effect, this paper adopts the binary and geographical distance spatial weight matrices of geographical adjacency relationship, and uses the spatial econometric model to study the economic mechanism of the role of digital economy in urban-rural gap from the time dimension and regional perspective. The research results are as follows. First, the development of digital economy can significantly narrow the urban-rural gap. After using the replacement core explanatory variable test, the results are still robust. Second, at the level of mechanism analysis, the digital economy will narrow the urban-rural gap through marketization, labor allocation and business environment. Third, the digital economy has a significantly negative direct effect on the urban-rural gap, that is, the development of the digital economy in the region significantly narrows the urban-rural gap in the region by virtue of the “agglomeration effect”. And the indirect effect is positive, that is, due to the existence of the “siphon effect”, the development of digital economy in the region will significantly expand the urban-rural gap between adjacent regions. On this basis, this paper puts forward corresponding policy suggestions from three aspects: cultivating digital fertile soil conducive to the digital development of rural areas, improving the institutional mechanism of factor marketization reform under the digital economy and constructing the sharing mechanism of digital economic achievements.