This paper combines knowledge from industrial clusters and enterprise growth theories to analyze the mechanism through which industrial cluster support affects the development of specialization, refinement, differentiation, and innovation (SRDI) among manufacturing SMEs and employs a sample of manufacturing SMEs in Zhejiang Province for empirical analysis. The findings indicate that industrial cluster support can effectively enhance the SRDI development level of manufacturing SMEs; however, the strength of industrial cluster support is moderated by both internal and external factors of the enterprises. Specifically, when manufacturing SMEs face severe “bottleneck” challenges, the supportive effect of industrial cluster support is more pronounced, whereas this supportive effect diminishes when manufacturing SMEs have higher levels of digital construction or cater to higher-level clients.