Abstract: ［Objective］ The CBTC (communication-based train control) system on urban rail transit lines has certain limitations in specific scenarios: when there are multiple protection sections along a route, the interlocking system cannot flexibly select protection sections based on the train forward direction, causing inability to meet the requirements of flexible and automatic route arrangement establishment. Therefore, there is a need to optimize the protection section trigger strategy. ［Method］ The basic principles of route triggering and protection section setup in CBTC system are briefly introduced, highlighting two typical problem scenarios under existing protection section control schemes. An optimization scheme for the protection section trigger strategy is proposed, where ATS (automatic train supervision) automatically selects the protection section direction and delegates it to the interlocking system. Taking scenario I (train skip-stop and turn-back to depot) as example, according to train dynamics characteristics, the train skip-stop performance before and after optimization is compared and analyzed. ［Result & Conclusion］ The case analysis results of train skip-stop and turn-back to depot scenario show that after optimizing the protection section control strategy, the time performance of train skip-stop is greatly improved. The proposed optimization method is feasible and can significantly enhance the flexibility of protection section handling, improving the efficiency of train skip-stop.