In the digital economy era，the digital reconstruction capability of pharmaceutical supply chains has become a critical foundation for internet-based healthcare enterprises to establish competitive advantages. The mechanism through which digital technology coupling facilitates the acquisition of new institutional legitimacy and drives the formation of dynamic capabilities warrants in-depth investigation. This study adopted a dual-case research approach，focusing on JD Health and AliHealth，to systematically explore the role of digital technology coupling in the digital reconstruction of pharmaceutical supply chains. The research revealed three key insights:（1） The coupling application of digital technologies in pharmaceutical supply chains cultivates enterprises' ambidextrous capabilities—agile responsiveness and collaborative co-creation—thereby forming a dynamic capability system for digital reconstruction； （2） The logic of vertically integrated and openly distributed digital technology coupling shapes differentiated pathways for dynamic capability development； （3） The digital reconstruction of pharmaceutical supply chains demonstrates a co-evolutionary mechanism between institutional pressure response and new institutional construction in emerging fields. Internet-based healthcare enterprises construct regulatory，normative，and cognitive legitimacy through interactions with multiple institutional actors，with digital technologies significantly accelerating the legitimacy acquisition process. This study extends the theoretical boundaries of dynamic capability theory and institutional entrepreneurship in digital contexts，and will provide a conceptual framework and managerial insights for the digital transformation of pharmaceutical supply chains.