To eliminate influence of temperature fluctuations on wind speed measurement with anemometer,design a kind of fiber Bragg grating( FBG) anemometer using principle of number counting effectively and stably measure wind speed. This kind of anemometer has a wind cup,which has a speed cam,and the counting device consists of speed cam and a balanceable cantilever on which FBG is pasted. Based on linear relationship between wind speed and revolving speed of the wind cup,build sensing model,then can calculate according to numbers of central light wave changes,calculate wind speed and monitor wind speed live in the aim area. Wind tunnel experiments show that wind speed sensor using principle of number counting start up wind speed is 0. 9 m / s,linearity is 6 % and sensitivity is 0. 65 r / m.