The invention discloses a coal gangue leaching and immersion testing device under a multi-field coupling effect. The coal gangue leaching and immersion testing device comprises an inner barrel, an outer barrel, a leaching solution barrel and a leaching solution collector, wherein the inner barrel is divided into a leaching solution collection region and a leaching region for filling a testing material through filtering and penetration plates; a liquid inlet plate capable of bearing pre-set pressure is arranged above the leaching region and a liquid inlet hole is formed in the liquid inlet plate; the leaching solution collection region is connected with the leaching solution collector; the leaching solution barrel is connected with the liquid inlet hole of the liquid inlet plate through a pipeline; quantitative saline water is filled into the outer barrel; the inner barrel is arranged in the outer barrel; a semiconductor chilling plate is arranged in the outer barrel. The testing devicedisclosed by the invention has the advantages of simple structure, reasonable structure and convenience for utilization; the testing device can be used for simulating a leaching and immersion test ofgoaf solid filler under the multi-field coupling effect of a stress field, a seepage field, a temperature field, an acid-alkali field and the like; a collected leaching solution is used for carryingout a heavy-metal element dissolution testing experiment, and basic data information is provided for solving the environment protection problem of solid filling in a coal mine goaf.