The invention discloses a temperature, humidity and wind speed integrated sensing system of a fiber grating. The system comprises a pump laser, a wavelength demodulator, a computer terminal, a wavelength division coupler, an optical fiber connector, a control line, a testing fiber 1 which is connected to a jump fiber in a testing environment, a testing fiber 2, and a temperature reference fiber. The three fibers comprise at least 13 testing points, the temperature, humidity and wind speed parameters of multiple points are obtained through measurement, wherein the two testing fibers and the temperature reference fiber are connected to three paths of measurement ports, the pump laser enters into the testing fiber 1 for measuring the wind speed parameter through the wavelength division coupler, and the pump laser is used for heating the high absorption loss fiber section connected to the testing fiber 1, which means that the a fiber hot wire is heated for wind speed measurement. According to the system, the synchronous high-precision measurement of the three parameters which are the environment temperature, the humidity and the wind speed can be realized.