The relationship between the investment in new infrastructure and the sustainable development of the digital economy in the Yellow River Basin was explored. Based on panel data from nine provinces in the Yellow River Basin from 2011 to 2021, indices for investment in new infrastructure and sustainable development of the digital economy were constructed. A two-way fixed effects model, robustness test, mediation effect and heterogeneity analysis was used to measure the effects of investment in new infrastructure on driving the sustainable development of the digital economy. The results show that investment in new infrastructure in the Yellow River Basin can directly and indirectly promote the sustainable development of the digital economy, and there are regional differences with a more significant promoting effect in the upstream areas than in the middle and lower reaches.