With the continuous advancement of urbanization, pipeline maintenance is facing a series of challenges: the number of newly added pipelines is increasing year by year, the existing old pipelines are constantly aging, and the basic information is not clear enough. The vast underground drainage pipeline network in cities, as a key infrastructure, is responsible for sewage discharge and flood prevention. Once there is a blockage or overload operation of the pipeline, it will cause damage to the pipeline system and further lead to problems such as black and odorous water bodies and urban flooding. It is particularly important to fully utilize the advantages of various pipeline detection technologies, and promptly grasp the defect types and leakage degrees of pipelines. This article analyzes the working principles, applicable environments, and advantages and disadvantages of internal and external detection technologies for underground pipelines in current urban infrastructure, providing certain references for the current urban drainage pipeline detection work.