The object of the invention is to provide a transmission conductor modal analysis method considering the change of operating temperature, which is carried out according to the following steps: step 1,calculating the elastic modulus ET of the conductor at the temperature according to the parameters of the conductor and the temperature T of the conductor during operation; step 2, calculating the length LT of the conductor under the temperature according to the structural parameters of the conductor, the running temperature T and the ET calculated in the step 1; step 3, calculating the rigidityEI of the conductor under the temperature according to the structural parameters of the conductor and the elastic modulus of each layer of the conductor; step 4, calculating the natural frequency omega nc of the conductor under the temperature through the wire structure parameter, the length LT calculated in the step 2 and the rigidity EI calculated in the step 3; step 5, judging the state of theconductor by using the existing conductor performance analysis method through the real-time operation of the transmission conductor acceleration and wind excitation. The method of the invention realizes the modal parameter identification method of the transmission line under the condition that the operating temperature changes.