The invention relates to an optical fiber humidity sensor used on a humidity detection device which comprises a wideband light source, an optical fiber coupler, a wavelength demodulation instrument, a single mode fiber and the optical fiber humidity sensor. The wideband light source and the wavelength demodulation instrument are respectively connected with the optical fiber coupler which is connected with the optical fiber humidity sensor through the single mode fiber. The humidity sensor comprises a solid photonic crystal fiber welded at the end portion of the single mode fiber in a fusion mode, wherein an air hole at the tail end of the solid photonic crystal fiber recesses to be a ball shape in a fusion mode, and a coating of polyving akohol serving as humidity sensitive materials are coated on the surface of the solid photonic crystal fiber. The manufacture method of the optical fiber humidity sensor comprises the steps that firstly, the solid photonic crystal fiber and the single mode fiber are welded in a fusion mode to be made into a sensing head; and the humidity sensitive material coating is coated on the solid photonic crystal fiber. The humidity sensor is free of packaging, simple in structure, intrinsically safe, high in sensitivity and low in manufacture cost. In addition, the manufacture process of the humidity sensor is simple and convenient.