In the context of fintech’s transformative impact on banking, many commercial banks blindly adopt emerging technologies, resulting in systemic inefficiencies. To address this, we propose a complex systems-based competitiveness evaluation framework guiding strategic fintech adjustments. First, the Delphi method identifies five fintech subsystems: big data, artificial intelligence, cloud computing, the Internet of Things, and blockchain. Next, an ANP model captures nonlinear dependencies and feedback loops among these subsystems, overcoming the limitations of linear hierarchical methods. Empirical validation using 16 listed Chinese banks demonstrates the model’s systemic coherence and practical utility. This study contributes to systems science by integrating complex adaptive systems (CAS) theory into competitiveness evaluation, shifting from firm-centric governance to ecosystem dynamics. It also offers banks a tool for adaptive strategy iteration in evolving fintech ecosystems.