Hydrogen is regarded as one of the promising candidates for next generation of renewable energy, and hydrogen-loaded natural gas (HCNG) is widely developed in fuel cell as clean energy.However, hydrogen is dangerous as a explosive gas, and therefore hydrogen concentration monitor and hydrogen leakage detection is required for industrial application safety.This paper reviews the developing work conducted at the National Engineering Laboratory for Fiber Optic Sensing Technologies, Wuhan University of Technology, fiber optic hydrogen sensors based on Pd-alloy thin films and Pt-loaded WO3 coatings have been intensively investigated.Hydrogen concentrations in range of 200-40000 ppm can be detected with monitoring resolution of 100 ppm and minimum detection threshold of 200 ppm.Also hydrogen concentration up to 20% in HCNG can be monitored based on Pd-alloy sensitive materials.Prototype of the proposed fiber-optic hydrogen sensing system has been realized and can be available for industrial safety application.