Combined with the scheme study of the detection and repair project of a regional road underground cavity in Shanghai, several methods for detection and evaluation of road cavities are proposed. The application research on the method and effect of non-destructive detection of geological radar cavities is carried out. The main causes of road cavities are analyzed, and several repair schemes targeted for road cavities are summarized and proposed. The research results can be used for reference in the detection, design and maintenance decisions of related projects in the future.