The invention provides an evaluation method for the operating condition of a line of a carbon fiber lead. The method comprises the steps: obtaining parameters of a high-tension voltage of a line of a carbon fiber lead, and recording closing and opening coil currents of the high-tension switch; determining whether the switch electrical and mechanical features of the high-tension switch are normal by analyzing waveforms of the closing and opening coil currents and a route curve during the movement of the switch; obtaining a real-time temperature value of a transformer by a transformer intelligent measurement and control instrument, and comparing the obtained temperature value with a preset temperature value corresponding to the model of the transformer; and obtaining the sag of the lead, calculating the temperature of the lead according to the sag of the lead, and determining the operating condition of a current line through an obtained environment parameter. According to the method, on-line automatic detection and control of the operating condition of a power transmission line can be achieved.