Abstract: Signaling system undergoes large amount of modification throughout lifespan, which not only affects rail transit operation safety directly, but also become the crucial reason triggering rail transit safety issues. The general modification safety management process applicable for signaling system is proposed. The signaling system modification is classified into 4 types: Type 1 (incremental change), Type 2 (corrective change), Type 3 (error revision), Type 4 (upgrade), and detailed explanation is provided respectively. The lifecycle phase affected by each type is introduced, risk analysis and assessment are carried out. Decision optimization is conducted for each type of modification and corresponding safety confirmation requirements are put forward. On the basis of categorizing and analyzing modification reasons, the signaling system modification safety management optimization process based on reason categorization is further proposed. The modification reasons for 4 delivered signaling system projects are counted and the proportion of each type is confirmed. Signaling system modification safety management optimization process can greatly reduce unnecessary investment, improving modification safety management efficiency.