With the research and development of surface plasmon theory and integrated optics technology, the way to enhance the detection sensitivity through the study of enhanced fluorescence properties on the surface of the sensitive membrane of optical sensors is getting more and more attention in the field of biomedical detection. An optical fiber-type fluorescence sensor based on surface-enhanced fluorescence (SEF) is proposed and analyzed through the finite element method. The simulation results show that the field enhancement factor reaches a maximum value of 12. 11 when the gold film thickness is 50nm and the Surface Plasmon Resonance (SPR) wavelength is 566 nm, at which time the fluorescence enhancement effect is better. The designed fiber optic sensor was processed by magnetron sputtering method, and the fluorescence detection platform was built and tested for the fluorescence emission intensity of Alexa Fluor 594 carboxylic acid(AF594-COOH). The experimental results show that the fluorescence intensity excited by the gold-plated multimode fiber is enhanced by a factor of 3. 35 compared to that of the non-gold-plated fiber.