The invention proposes a method for positioning a fiber composite overhead ground wire. The method comprises: using a Brillouin optical time domain reflectometer to acquire the Brillouin frequency shift signal inside the fiber composite overhead ground wire in real time; pre-processing the Brillouin frequency shift signal to obtain the data sequence of the fiber distribution type measuring spots rowed along the wire sequence; extracting from the data sequence the characteristics positioning data; based on the characteristics positioning data, determining the geographical positions of various rod towers of the power transmission line on the measuring fiber; and according to the geographical positions of the rod towers on the measuring fiber and in combination with the geographical coordinates of the rod towers in the line parameters, determining the real time geographical coordinates of the fiber distribution type measuring spots. The invention further proposes a device for positioning the fiber composite overhead ground wire. With the method, high positioning accuracy is achieved and real time monitoring of the geographical position information of the overhead ground wire becomes possible.