The technical characteristics, equipment, and working principle of using 3D ground penetrating radar to detect subsidence and clearance are introduced. A detailed description of the subsidence and clearance situation in a specific section of an asphalt road, as well as the process of conducting non-destructive detection using 3D ground penetrating radar are conducted. The detection results before treatment are utilized to determine the degree and position of the void, and to calculate the position, area, and elevation difference of the subsidence. By comparing two sections with different causes of subsidence and clearance, the causes of subsidence and clearance are analyzed, and corresponding treatment measures are proposed. The test results after treatment are used to evaluate the effectiveness of treatment measures such as grouting and paving. The findings demonstrate that the 3D ground-penetrating radar system can accurately detect the extent, location, and causes of subsidence and clearance in asphalt pavement. Based on the detection results, targeted treatment measures are put forward, and their feasibility and effectiveness in achieving the desired treatment outcomes are evaluated.