Abstract: Under the background of regional integration in the Yangtze River Delta, the research on the balance of space allocation in the Grade Ⅲ Level A hospitals will help coordinate the high-quality medical resources at the regional level, and provide support for promoting the integration of regional medical services. In this study, the gravity-based 2-step floating catchment area（2SFCA) method was used to quantitatively analyze the impact of different service radius and distance attenuation parameter β on the accessibility of the Grade Ⅲ Level A hospitals, and analyze the spatial distribution characteristics of accessibility. The coupling coordination degree model was then used to analyze the coordinated development level of supply and demand of the Grade Ⅲ Level A hospitals in each district and county. The results showed that:（1) By narrowing the service radius and increasing the distance attenuation parameter, the average supply level of the Grade Ⅲ Level A hospitals could be improved, but the gap between the districts and counties would be increased. Additionally, the blind expansion of the service radius would reduce the average level of supply, and the gap between districts and counties would also be significantly increased when the distance attenuation parameter was high. Therefore, the key to improving the supply level of Grade Ⅲ Level A hospitals is continuously optimizing the spatial layout of the Grade Ⅲ Level A hospitals to make their service radius relatively reasonable, and guide residents to seek medical treatment in a certain range.（2) the polarization characteristics of accessibility of class A hospitals are obvious. The development of high-speed rail can promote the formation of high-value continuous areas with transportation advantages, as shown in the metropolitan areas of Shanghai, Hangzhou, Suzhou, Wuxi, Changzhou and Nanjing. On the contrary, the difficulties of acquiring proper medical treatment faced by residents in the traffic disadvantaged areas, such as Western Anhui, Western Zhejiang and Eastern Jiangsu, may be aggravated. Therefore, it is necessary to continuously promote the synchronous construction of the Grade Ⅲ Level A hospitals and transportation infrastructure.（3) At present, the overall supply-demand relationship of the Grade Ⅲ Level A hospitals in each district and county is relatively harmonious, but the coordination level is relatively low. The imbalance areas of supply and demand are concentrated in Anhui and Northern Jiangsu and southern Zhejiang, while the areas in northern Zhejiang and southern Jiangsu have formed a continuous balance of supply and demand. Counties with higher supply than demand are mainly distributed in Anhui and Jiangsu provinces, which are the key areas to improve the utilization efficiency of the Grade Ⅲ Level A hospitals.