The pipeline electric heater uses a digital display temperature regulator, a solid state relay and a temperature measuring element to form a measurement, adjustment and control loop. During the electric heating process, the temperature measuring element sends the electrical signal of the pipeline electric heater outlet temperature to the digital display temperature regulator. Zoom in and display the measured temperature value after comparison. At the same time, output the signal to the solid-state relay input terminal to control the heater, so that the control cabinet has good control accuracy and adjustment characteristics. The interlocking device can be used to remotely start and close the pipeline electric heater.