The digital transformation of small and medium-sized manufacturing enterprises is influenced by various factors, and the relationship between them is not yet clear. Studying the factors that affect the digital transformation of small and medium-sized enterprises can promote the digital transformation process of small and medium-sized manufacturing enterprises. On the basis of summarizing literature and expert recommendations, this study identified the influencing factors in the digital transformation process of small and medium-sized manufacturing enterprises, and analyzed the key influencing factors using a combined method of DEMATEL-ISM-MICMAC (Decision-Making Test and Evaluation Laboratory-Interpretive Structural Model-Matrices Impacts Croises-Multiplication Appliance Classement). Research has found that digital policies, market demand, business model innovation, third-party data-driven services, and the digital foundation of enterprises are key factors in the process of digital transformation. In addition, the causal factors in the DEMATEL method, the essential factors in the ISM method analysis, and the independent factors in the MICMAC technique analysis can mutually support and complement each other. This study enriches the methodology for studying the factors of digital transformation and provides reference for the digital transformation of small and medium-sized manufacturing enterprises and government policy formulation.