Abstract: As one of nondestructive testing techniques, the radar method has seen considerable application in recent years in defect detection of reinforced concrete structures. This paper reviewed the basic principle of the radar method and its application in the structural defect detection of reinforced concrete voids, cracks, compactness, moisture erosion, protective layer thickness, reinforcement configuration, corrosion of reinforcement, and other aspects of the current situation. It also analyzed the problems and difficulties in the practical application of the radar method. The paper concluded with a discussion of future research directions, including the detection of small cracks measuring less than 3 mm, the enhancement of signal anti-jamming and data processing capabilities, the integration of the radar method with other nondestructive testing techniques, and the advancement of detection accuracy and efficiency through artificial intelligence technology.