Given the unclear scope and lack of basic data on the small kiln destruction area caused by room-pillar mining in Guojiawan Coal Mine, a method combining geophysical exploration, drilling, and three-dimensional spatial scanning technology was used to conduct a detailed exploration of the goaf area, roof status and water accumulation, internal tunnels, and coal pillar size. First, the goaf area and different partitions were delineated by interpreting the abnormal area through ground transient electromagnetic physical properties and verifying the exploration results through drilling. Then, the three-dimensional spatial scanning technology was used to conduct detailed scanning and observation of the internal space of the water and water-free goaf areas, and high-precision technical data such as tunnel width, goaf height, coal pillar size within a certain range around the bottom of the borehole were obtained. The internal and external morphology of the goaf was obtained through three-dimensional modeling. The research method in this paper can provide support for the exploration of small kiln destruction areas, accurate data measurement of internal space, stability assessment of goaf areas, and disaster prevention.