Abstract: Urban underground drainage pipes are an important part of infrastructure and an important guarantee for environmental cleanliness. Because there are many types of defects in urban underground drainage pipelines, complex structures and different standards, it is difficult to accurately identify hidden pipeline hazards and eliminate diseases. Urban drainage pipeline inspection is the basis for pipeline evaluation and an important prerequisite for pipeline repair. In order to identify defects in underground drainage pipes, inspections should be carried out during drainage pipe repairs. The detection of urban underground drainage pipes affects the drainage effect of the entire city, and scientific detection methods are used to ensure uninterrupted drainage of underground drainage pipes. Based on this, this paper explains the classification of drainage pipeline defect detection technology, discusses the pipeline defect analysis technology, and puts forward specific drainage pipeline repair countermeasures, in order to provide some reference for related projects.