Abstract: Based on the principle of ground penetrating radar, the geophysical characteristics of underground disease bodies and their wave group characteristics reflected in ground penetrating radar signals are analyzed. At the same time, the common electromagnetic interferences on urban roads and their characteristics in ground penetrating radar signals are summarized. The results show that correctly identifying useful signals and eliminating interference signals is crucial for improving the accuracy of geological radar interpretation. Combined with engineering practice, the geological radar method can achieve good results in detecting urban road collapse diseases.