Based on the panel data of 40 sample countries along “the Belt and Road” from 2010 to 2018, this paper conducts an empirical test on the influence mechanism and spatial spillovers and nonlinear effect of digital economy on innovation performance from the overall and regional dimensions. The results show that :(1) Digital economy can significantly improve the innovation performance of the countries along “the Belt and Road”, and has become an important driving force for the improvement of innovation performance of the countries along “the Belt and Road”. (2) Digital economy can indirectly improve the innovation performance of countries along “the Belt and Road” by accelerating the upgrading of industrial structure. (3) The innovation spillover effect of digital economy has the nonlinear characteristics of positive and significant increase of “marginal effect”, and the industrial structure upgrading as a mediating factor can also positively strengthen the nonlinear innovation spillover effect of digital economy. (4) There is regional heterogeneity in the promotion effect of digital economy on the innovation performance of countries along “the Belt and Road”, and the innovation dividend of digital economy in sample countries in Europe is obviously higher than that in sample countries in Asia and Africa. Based on the empirical conclusion, the paper puts forward some countermeasures and suggestions to promote the development process of digital economy and innovation performance of countries along “the Belt and Road”.