As subway construction in China continues, the network operation mode of subway emerges, and more transfer nodes are created. Due to planning and other factors, the earlierbuilt subway lines did not reserve future transfer access conditions. Thus, when new lines are built, the existing stations often undergo transfer transformation and upgrading along with the new stations. Among the key tasks involved, the communication transmission system transformation and upgrading is crucial. The communication system is the traffic nerve of urban rail, which consists of public security communication system, civil communication system, and special communication system. It supports the information exchange between the control center and the stations and vehicles, and provides stable communication service for passengers. This paper examines the communication room transformation and communication capacity expansion requirements resulting from the transfer station transformation under the existing line operation conditions, and proposes the enhanced MSTP construction scheme for public security transmission system and the backbone transmission system OTN construction scheme. Xitucheng Station of Beijing Metro Line 10 intersects with the newly built metro Changnan Line, and the transfer station changes in building structure and function have raised new requirements for the communication system equipment deployment and upgrade. This paper applies the design scheme to the transfer project, verifies the rationality of the proposed scheme, and the research results offer an application reference scheme for the communication system upgrade of the existing station transfer transformation.