In this paper, a precision cylindrical micropore with a diameter of 20 μm near the end face of a single-mode optical fiber was fabricated by means of femtosecond laser oil-assisted machining method. A Fabry-Perot sensor with obvious light beat and Vernier effect was formed through the micropores and the end face of the optical fiber, which realized the measurement of environmental parameters. Experimental results show that the sensor has a good linear response to external temperature, humidity, refractive index, and gas pressure. The sensor exhibits a cryogenic sensitivity of -0.0669 dB/℃, a humidity sensitivity of 0.74 nm/%RH, a refractive index sensitivity of 6.5 nm/RIU, a high temperature sensitivity of 12.23 pm/℃, and a gas pressure sensitivity of 1.743 dB/MPa. The sensor has the advantages of simple fabrication, stable performance, and compact structure.