Objective:To introduce a fiber-optic fluorescent biosensor for choline.Methods:The choline fiber-optic biosensor designd included a LED,a bifurcated fiber,two kinds of filter,and a spectrometer.T he sensing end of the film was coated with Nafion film dispersed with choline oxidase and oxygen sensitive luminescent Ru(Ⅱ)complex.Results:The lowest limit of this choline fiber-optic biosensor for testing was 1×10-9mol/L with a respondence time T≤10 sec.Meanwhile,the sensor had a high anti-jamming ability.Conclusion:The fluorescence intensity of Ru(Ⅱ)is related to the choline concentration.The choline fiber-optic biosensor proves to be a low-cost,high-performance and portable apparatus.