Abstract: In view of the collapse and crack of a road in Hangzhou city, the transient surface wave method is used for detecting the underground diseases. Based on the ground wave velocity tests, the stratum properties under different conditions and the distribution of underground diseases of the road can be determined, which provides timely and accurate data for handling its safety hazards. The detected results show that the soil mass is loose within 7 m below the road, and the suggestions given are grouting reinforcement in some areas and removal of surface gravel in some areas. The image of transient surface wave method is intuitive, economical and fast, which can identify the diseases with potential engineering disasters, and it provides sufficient scientific basis for the repair and maintenance of roads.