In order to realize the effective detection of volatile organic compounds in a narrow environment, a fiber-optic volatile organic compound sensor based on the probe structure is proposed in this paper. The sensoris connected by a single-mode fiber and a hollow-core fiber with a length of about 130m. The hollow-core fiber is embedded with a polydimethylsiloxane film with a thickness of about 15m. The size of the final sensor is only rm150m. Single-mode fiber, hollow-core fiber and polydimethylsiloxane film together constitute a Fabry-Perot cavity interferometer. When the polydimethylsiloxane film absorbs volatile organic compounds, it will cause its own volume expansion, which will change the Fabry-Perot cavity length and cause the interference wavelength to shift. The experimental results show that: First, the sensitivity of the proposed optical fiber volatile organic compound sensor based on the probe structure is 2.0 pm/ppm in the measurement range of 0～9 000 ppm isopropanol concentration, and when the minimum resolution of the spectrometer is 0.02 nm, the sensor has a detection limit of 10 ppm for volatile organic. Secondly, the sensor also showed good stability and repeatability. In the 30-minute stability test experiment, the actual measurement error range of the sensor was ±30 ppm, indicating good stability. Three repeatability experiments also verified that the sensor has good repeatability. Finally, the response time of the sensor is less than 42 s, indicating that it has a faster response speed. Overall, the sensor has high sensitivity and low detection limit in the detection of volatile organic compounds, good stability and repeatability, and fast response speed. Moreover, the manufacturing cost of the sensor itself is low, the production process is simple, and large-scale manufacturing can be realized. When measuring, the sensor is not limited by the space environment and can detect volatile organic compounds in a narrow environment.