The competitive patterns among firms in the digital age have undergone significant changes. How digital firms can compete with leading firms and achieve incremental catch-up becomes an important issue that needs to be addressed. From the perspective of substitutive innovation, the impact of digital search on the incremental catch-up performance of digital firms was analyzed, and the mediating role of substitutive innovation behavior and the moderating role of inter-organizational dependence were investigated. Based on a sample of digital enterprises that provide digital technologies, products and services, the empirical test was conducted using multiple regression analysis. The results show that digital search is a supportive condition for digital firms to achieve incremental catch-up performance, and both prospective and reactive search dimensions positively influence the incremental catch-up performance of these firms. Leapfrogging substitution behavior and coherent substitution behavior mediate the relationship between digital search and incremental catch-up performance. Sensitivity dependence has no significant moderating effect between substitutive innovation behavior and incremental catch-up performance. Vulnerability dependence negatively moderates the effect of leapfrogging substitution behavior on incremental catch-up performance, while the moderating effect on coherent substitution behavior and incremental catch-up performance is not significant. The conclusions reveal the process mechanism of incremental catch-up of latecomer digital firms, which provides theoretical and practical implications for world-class firms seeking to achieve breakthroughs.