Abstract: Fiber optic oxygen sensors based on the principle of fluorescence quenching have always been the focus by many research works. A simple and low-cost method for manufacturing fiber optic oxygen sensor was introduced.Based on the principle of fluorescence quenching, this method was realized by the fluorescence material platinum octaethyl porphyrin (PtOEP) coated on the fiber end.In the sensor, the fluorescent material was excited by the violet light of 395 nm and guided by the Y-shaped optical fibers, and furthermore, the luminescence timing diagram of the fluorescence was recorded using a spectrometer USB2000+ of Xipu Optoelectronics.The value of PtOEP (I₀/I₁₀₀)-1 is 0.78, that is to say, the sensitinity of the sensor is 0.78, and the Stern-Volmer diagram shows good linearity characteristics, and the response time from the air environment to the oxygen is 5 s while the response time from oxygen to air environment is 24 s.These results show that the fiber optic oxygen sensor based on fluorescence quenching principle has higher sensitivity and faster response time.