Low-dimensional nanomaterials are able to improve the contact area b etween the materials and the gas molecules because of the large specific surface area,which is promising to enhance the sensitivity of hydrogen sensors.In this study,a reflective optical fibe r sensor based on centrifugal deposited Au-Pd core-shell nanoparticles has been designed and fabricated.Through a seed solution growth method,the cube gold core with 40nm size was syn thesized in aqueous solution.Then,200μL Pd growth solution was added in Au core solution and reduced as 10nm thick Pd shell to obtain Au-Pd core-shell nanoparticles with the size of about 62nm.After a centrifugal deposition process at 4000rpm for 8min,4mL nanopart icle solution was deposited on a 10mm×10mm quartz glass substrate to prepare hydrogen sensitive nanoparticle f ilms with a thickness of 200nm.A reflective optical fiber bundle sensor with double-light-route c ompensation has been built to characterize the sensitivity of the film for various hydrogen concent rations.The experimental results show that the sensor has a high sensitivity to hydrogen in the concentration range of 0.1%～4%.After a curing process in the first few cycles,the sensor exhibits a good stability and repeatability in the multiple pass/vent cycles.With the decrea se of hydrogen concentration,the sensitivity of the sensor increases nonlinearly,which has a great advantage in the low concentration hydrogen detection.