Understanding the business model phenomenon in complex business environments necessitates a dynamic ecosystem perspective. However, the lack of "construct clarity" significantly impedes this understanding, persistently challenging the theoretical and empirical development of business models. Through a theory-driven integrative literature review, this study aims to overcome this obstacle by leveraging Bertalanffy’s general systems theory (GST) and its core "open system" logic to clarify the business model construct within an ecosystem context. Reviewing 246 sources, the study identifies key issues within the research gaps and applies GST to critically analyse existing research on conceptualizing business models. It thereby defines a business model as an open system modelling iterative activities at the ecosystem level and enhances construct clarity across four basic elements: definition, scope condition, relationship with related concepts, and theoretical coherence. Additionally, the study introduces the "EBM" framework, illustrating how a business model's interconnected structure and dynamic nature align with open system logic, leading to the proposal of six research themes for future theoretical development. By bridging the research gap, this study clarifies a fundamental strategic and organizational concept, fostering a mindset-shifting understanding of business models from a broader, dynamic open system perspective while promoting interdisciplinary communication through the "unity in diversity" capability of GST.