This study investigates the effectiveness of enterprise financial management systems through the lens of module collaboration, integrating accounting, settlement, funds, and processes into a unified analytical framework. While existing literature predominantly examines individual financial functions in isolation, the systemic mechanisms by which these modules interact and collectively contribute to organizational goals remain underexplored. Drawing upon synergy theory and systems thinking, this research adopts a qualitative case study approach, conducting semi-structured interviews and document analyses with four Chinese manufacturing firms at varying stages of financial digitalization. The findings reveal three primary synergy mechanisms—data standardization, process coupling, and cross-functional governance—that significantly enhance information transparency, operational efficiency, and risk resilience. Conversely, module fragmentation, incompatible information systems, and conflicting performance incentives are identified as critical barriers to effective collaboration. Furthermore, this study proposes a maturity model for module collaboration, delineating four evolutionary stages: isolation, connection, integration, and intelligence. The research contributes to management accounting theory by shifting the analytical focus from functional optimization to systemic synergy, while offering practitioners a diagnostic tool for identifying collaboration bottlenecks and prioritizing improvement initiatives. This study is limited by its small sample size and suggests future large-scale surveys to validate the proposed model.