Kuaishou E-commerce Live Streaming Technology Team introduces Live Captioning Engineering, reducing end-to-end latency from 1.5-2 seconds to 400-500 milliseconds and cutting character error rate from 7.81% to 3.51%. The system supports millions of concurrent users through a four-stage pipeline: automatic speech recognition, PTS alignment, cascading distribution, and client-side rendering. A key innovation is the streaming revision mechanism using sentenceId, revision, and player timeline to stabilize continuously updated captions without flickering. This represents the first systematic engineering approach for high-concurrency, real-time e-commerce live streaming scenarios, offering valuable insights for building robust real-time AI systems.