This study comprehensively employs the entropy method, coupling coordination degree model, and grey relational degree model to measure and analyze the comprehensive development level, coupling coordination degree, and driving factors of medical services, medical security, and the pharmaceutical industry ("three medicals") in the Yangtze River Delta region. The results show that the overall comprehensive development level of the "three medicals" in the Yangtze River Delta region has improved, but the development of the pharmaceutical industry is relatively lagging behind. The coupling coordination degree of the "three medicals" in the region is on the rise and has entered the intermediate coordination stage as a whole, but there is still room for optimization. There are significant spatial differences in the coupling coordination degree among provinces and cities, with Anhui Province and Shanghai lagging behind in terms of coordination level. The efficiency of medical services and the scale of the pharmaceutical industry are the key factors driving the coupling and coordinated development of the "three medicals". Based on this, it is necessary to address the shortcomings in the development of the pharmaceutical industry, remove inter-provincial collaboration and data sharing barriers, implement differentiated strategies for the lagging coordination between Anhui and Shanghai, and promote a "dual-wheel drive" path of improving the efficiency of medical services and expanding the scale of the pharmaceutical industry.