The invention relates to an accurate positioning and detecting method and device for damages of an underground metal pipeline anticorrosive coating. The method comprises the following steps: a current interrupter periodically turns on or off a constant current source through the constant current source, and provides excitation signals for an underground pipeline; the ground voltages of two pointsalong the underground pipeline route are measured by utilizing two saturation copper sulfate reference electrode detection canes which are connected with a signal measurement processor respectively; the signal measurement processor measures, records and displays the turn-on and turn-off of the pipe ground voltages; and the position of the damaged part of the underground pipeline can be determinedaccording to the pipe ground turn-on and turn-off voltages. Through the method, the position of the damage point of the anticorrosive coating can be confirmed accurately, the detection accuracy of the damage for the underground pipeline anticorrosive coating is improved, and important guarantee is provided for mastering the normal operation situation of the pipeline, ensuring the safe operation of the pipeline and the convenience for pipeline maintenance and management.