The invention discloses an underground pipe column galvanic corrosion detecting device, and the device comprises a galvanic corrosion detecting element, two lining caps, two protective caps and a lining bracket, wherein the galvanic corrosion detecting element is configured as a galvanic corrosion detecting element that is composed of metal test plates made of at least two kinds of metal and a galvanic couple formed by the metal test plates; the metal test plates are arranged at adjustable intervals; the two lining caps are used for fixedly connecting each metal test plate by clamping from the two ends of each metal test plate respectively; the two lining caps are respectively fixed in the two protective caps; and the galvanic corrosion detecting element, the lining caps and the protective caps are connected to form an overall structure and fixed at the lining bracket. The underground pipe column galvanic corrosion detecting device can be connected with an underground pipe column and directly used for an underground test so that the test working condition is the same as the actual working condition, and the accuracy and the reliability of test data are ensured. Moreover, the exposed area ratio of any two metal test plates can be regulated as needed so as to ensure the accuracy.