The invention provides a Fabry-Perot interferometric sensor based on a photonic crystal fiber and a manufacturing method thereof. The sensor is composed of a conventional communication single-mode fiber and a solid photonic crystal fiber, wherein the conventional communication single-mode fiber and the solid photonic crystal fiber are welded by using a certain welding method. Because air holes ona cladding of the photonic crystal fiber collapse, an air cavity (namely, an F-P cavity) is formed between the two fibers, and the two end faces (namely, the front and rear surfaces of the air cavity) of the photonic crystal fiber and the single-mode fiber are two reflecting surfaces of the F-P cavity. The solid photonic crystal fiber is made of a single material, and does not cause the mismatching of thermal expansion coefficients of materials in the process of temperature variation, thereby ensuring that the influence of temperature variation on the interferometric sensor is small; in the manufacturing process, only a fiber cutting and welding process is used, therefore, the preparation process is simple; by using the sensor, high-fineness and high-contrast interference fringes can be obtained, therefore, the sensor has a great application potential in large-capacity and quasi-distributed sensing systems; and the sensor is in an all-fiber structure, and has the advantages of small volume, good robustness and low cost.