Geodesic radar method is a non-destructive geophysical method to detect underground geological structure based on the differences in conductivity, magnetism and dielectric constants of different substances. This method has the advantages of economy, fast, continuous, accurate, non-destructive, non-contact, etc. It is applicable to both metal and non-metal pipelines, and it is the preferred tool for underground pipeline detection. In this paper, the geological radar method is used to detect the complex pipe network around Daning Reservoir in detail by laying out multiple detection lines. It provides basic support for the later pipe network rectification. The research results can provide experience for the detection of the complex pipe network in the urban reservoir.