Abstract: Currently, the signaling system format selection of city rail transit is facing significant challenges due to its crucial role in determining the line operation organizationmanagement mode. Therefore, it is necessary to conduct indepth research on relevant factors that influence the city rail transit signaling system and select an appropriate signaling system format. Method: The problems existing in the selection of signaling system formats are introduced, together with the main signaling system formats in China. The factors affecting this selection are analyzed, and the considerations for choosing a signaling system format are summarized. Result & Conclusion: The existing CBTC (communicationbased train control) signaling system and CTCS2 (Chinese train control system 2) cannot fully meet the operational requirements of city rail transit in terms of publictransitoriented operations and network interoperability. Currently, the main signaling system formats available for city rail transit include CBTC, CTCS2, and STCScompatible (signaling and train control system). The factors influencing the selection of city rail transit signaling system can be broadly categorized into determinative factors such as system technical limitations, operationmanagement mode, and networking operational requirements, as well as important factors such as passenger flow characteristics, investment efficiency, equipment failure impact, and other factors including technological development, passenger experience, service comfort, safety, and external environmental impacts.