To effectively monitor the hydrogen leakage of hydrogen pipeline, a quasi-distributed real-time online hydrogen leakage monitoring system based on -OTDR is proposed in this paper. First, the cladding of the single-mode fiber was removed, and then the hydrogen-sensitive palladium film was coated on the surface of fiber without cladding by using the chemical coating method to response the hydrogen, thereafter, the hydrophobic sol was coated on the palladium film. Second, the hydrophobic sol coated fiber was installed in the PTFE channel. Finally, the hydrogen leak of the hydrogen pipeline was monitored by using the Φ-OTDR distributed hydrogen sensing system. The results show that the optical fiber Φ-OTDR distributed hydrogen sensing system can accurately respond to small changes in hydrogen concentration around the hydrogen pipeline. The response time was 60 s, the position resolution was 50 mm, and the lower limit of detection for hydrogen concentration was 1 000×10-6. The research results show that the measurement system based on optical fiber Φ-OTDR can accurately detect hydrogen leaks in hydrogen pipelines over a long distance and large range.