Abstract: In the complex working environment of coal mines, accurately detecting geological conditions such as fissures, separations, and fractured zones inside boreholes is a crucial step in preventing major safety accidents. With the iterative upgrading of intelligent mining technologies, the demand for the precision and timeliness of transparent geological models has increased exponentially, posing unprecedented challenges to borehole detection techniques. There is an urgent need to achieve a realistic representation of geological structures and precise detection of fine structures. Existing various borehole detection instruments have shortcomings: the viewing angle of camera probes is generally limited, making it difficult to fully capture borehole wall information; the video clarity is poor, resulting in the failure to clearly present key details such as micro-fractures; the effect of image unfolding and stitching is unsatisfactory, which affects the integrity and accuracy of geological data. To address these issues, a visual borehole detection solution is proposed, and a mining rotary visual borehole detector is designed. The instrument adopts a novel borehole imaging technology, and the imaging probe can switch freely between forward viewing and side viewing at any angle, enabling clear acquisition of both the front structures and side details inside the borehole; it supports focal length adjustment and brightness adjustment functions to adapt to different detection environments; a unique lens self-cleaning device effectively addresses lens contamination caused by dust and mud in underground mines. In terms of video image processing, the rectangular image unfolding algorithm based on borehole center positioning and the video image stitching algorithm based on feature matching eliminate interference caused by natural jitter and rotation of the camera, significantly improving the unfolding and stitching quality of panoramic borehole images. Verified through ground and underground borehole tests, the mining rotary visual borehole detector has demonstrated excellent performance: it features high video image resolution with clear and complete frames, capable of accurately presenting subtle structures such as millimeter-scale fractures on the borehole wall; the measured data is stable and reliable, and the error control fully meets industry standards; it has a wide range of application scenarios, suitable for various boreholes including water exploration and drainage holes, gas drainage holes, anchor holes, and geological exploration holes, realizing the true reproduction and accurate detection of internal structures for borehole.