A fiber-optic evanescent wave biosenor has been developed which transmitted excitation laser beam and fluorescence signal through fiber bundle.Based on the theory of evanescent wave and mode matching in probe,the geometric figure of probe was designed,and five group probes were made.According to needs,some of them with Cy5 were also labeled.Then,probes were put in air and water,and the signal of the fiber-optic biosensor was examined respectively.Comparing the different results between labeled probe and unlabeled one,the existing of fluorescence signal in fiber-optic biosensor detected signal and the feasibility of the designed fiber-optic biosensor were confirmed and proved respectively.