Optical humidity measurement is essential in current industry, especially in environment with adverse electromagnetic field and strong corrosion. This paper focus on the fabrication and test of a novel fiber bragg grating based humidity sensor. The sensor is fabricated by uniformly coating humidity sensitive material on fiber bragg grating. The sensing characteristic test of the sensor shows: the wavelength shift following humidity is linear; the minimum response time of the 2-layer coated sensor is 10 s with sensitive coefficient can be controlled by changing coating time; hygroscopic hysteresis of 3-layer coated sensor is 2.7`%RH. Therefore, the sensor is promising to be used to meet the quick response and in vivo measurement demand in industry.