Abstract: Due to the unique underground sand and gravel layer structure and large-scale development and utilization of underground space, road collapse disasters caused by underground disease bodies have occurred frequently in Chengdu City. The ground penetrating radar method was used to detect underground cavities and voids on both sides of municipal drainage pipelines in the central region of Chengdu City. The distribution pattern of cavities and voids and their relationship with subway shield construction were discussed. The results show that a total of 811 cavities and voids were identified in the study area, with the average clearance and volume of the cavity being 0.41 m and 1.86 m³, and the average clearance and volume of the void being 0.12 m and 0.52 m³. The risk levels of cavity and void were basically rated as level Ⅳ and level Ⅲ. One hundred and seventy cavities and voids were found near the subway line, concentrating on Subway Line 3. The overall distribution density of disease bodies in the area is 0.72 per km, the distribution density of the disease bodies passing through the subway lines is about 1.07 per km, and the distribution density of those not passing through the subway road is 0.66 per km. The disease bodies are mainly distributed in the southern part and the pore phreatic area with loose accumulated sand gravel layer, which is also the area with dense subway traffic lines. The river system has little impact on the formation of shallow disease bodies, indicating that the subway shield construction induces the formation of underground disease bodies to a certain extent, under the special environment of sand gravel layer. The research results can provide basis for monitoring, early warning, and treatment of urban underground disease bodies.