Building internationally competitive digital industry clusters not only serves as a crucial strategic initiative to strengthen,optimize, and expand China’s digital economy but also profoundly influences the formulation and adjustment of enterprise internationalization strategies. Based on China’s micro-level enterprise data, this paper empirically examines the impact of digital industry agglomeration on the adjustment of Chinese firms’ export product scope. The findings reveal that digital industry agglomeration significantly promotes the expansion of Chinese enterprises’ export product ranges. The underlying mechanisms include facilitating knowledge spillovers, reducing business operation costs, and creating export information advantages. Further analysis indicates that the effects of digital industry agglomeration on firms’ export product scope adjustments exhibit heterogeneity across regional digital economy development levels, enterprise export trade modes, and ownership types. Specifically, it plays a more pronounced role in expanding export product ranges for firms in digital economy catch-up regions, general trade enterprises, and domestically owned enterprises. Additionally, monopolistic digital industry agglomeration demonstrates greater potential to promote export product diversification, whereas competitive digital industry agglomeration tends to constrain such expansion. This study offers policy implications for optimizing the digital economy development environment, fostering internationally competitive digital industry clusters, and promoting the diversified development of enterprise export products.