The invention discloses a method for measuring the temperature of a conductor externally covered by insulation material. The method comprises the following steps: establishing a heat transfer equation of the conductor under a heat stable state, and establishing the heat transfer equation based on heat flux balance and with heat radiation of the conductor body to the insulation layer being neglected; and measuring environment space temperature of the conductor and temperature of conductor insulation layer outer wall and obtaining parameter values and carrying out calculating through the heat transfer equation to obtain the temperature of the conductor body. According to the method for measuring the temperature of the conductor externally covered by the insulation material, the heat transfer equation is established by utilizing energy conservation laws in thermodynamics and based on heat flux balance of the conductor under the heat stable state, and the temperature of the conductor body is obtained indirectly by measuring the environment space temperature of the conductor and the temperature of the conductor insulation layer outer wall; and measurement reliability is high.