Objective The commercial development around subway stations is increasingly linked to subway lines. Studying the coupling between the two is of great significance for optimizing urban commercial layout and traffic planning.

Method A total of 77 stations in 3 lines of Xiamen Metro are selected, to determine the distribution of subway stations participating in the research and the influence range of station area. A research technical route for the coupling between retail commercial space and subway station is established, and the calculation formulas of kernel density analysis method, entropy weight method and coupling coordination degree model are expounded. Based on the POI (point of interest) data of retail business in Xiamen City, the kernel density analysis method is used to analyze the following six types of commercial POI data, such as convenience stores, catering stores, supermarkets, home building materials stores, specialty stores (sporting goods) and shopping centers, and four subway stations with high commercial vitality are obtained. The data of these four subway stations are selected to modify the coupling coordination degree model algorithm. A new coupling coordination degree model of retail commercial facilities and subway stations is constructed, and the coupling coordination relationship between retail commercial space and subway stations is quantitatively analyzed.

Result and Conclusion The modified coupling coordination degree model can effectively evaluate the coupling degree between subway stations and commercial space. Among the four subway stations, Lianban Station is highly coordinated with the surrounding commercial facilities, indicating that its commercial layout and subway passenger flow form a benign interaction; the other three sites are slightly out of balance, indicating that there is still room for the optimization of site commercial facilities or spatial planning.