Abstract: Aiming at the safety problems such as corrosion and leakage of buried pipelines, this paper presents a detection method for practical engineering applications, namely, trench-less weak magnetic field detection of buried pipelines. The principle of weak side detection and defect location algorithm are briefly described, and the feasibility of weak magnetic detection method is verified. The pipeline with artificial defect was tested and analyzed quantitatively by the self-developed weak magnetic field tester. The results show that the method is effective in identifying the defects of buried pipelines. It is concluded that pipelines can be safely inspected in trench-less manner and at any time and that two-dimensional imaging of pipe defects can also be achieved.