The invention discloses a high-voltage transmission line construction distance early warning device and method, and the device comprises a measurement end and an alarm end, and the circuit structuresof the measurement end and the alarm end are installed in a shell and are powered by a power module. The electric field sensor at the measurement end is connected with the input end of a controller through a signal processing circuit, a distance measuring sensor is connected with the input end of the controller, and the controller is connected with a wireless transmission module; an alarm end wireless data transmission module is connected with the controller, a working mode setting key is installed on the machine shell and connected into the controller through a working mode setting module, the output end of the controller is connected with a voice control module and a light control module, the voice control module is connected with an alarm and a buzzer, and the light control module is connected with a light emitting diode. The measurement equipment and the alarm equipment which are of a split structure are arranged, the measurement equipment can be arranged at the top end of the construction equipment, the operator holds the alarm equipment by hand, long-distance detection and alarm are achieved and the working environment of large mechanical equipment is met.