In the case of GPS signal loss of the unmanned aerial vehicle (UAV), the auxiliary visual recognition accuracy of the test pile is a key factor affecting the automatic inspection of oil and gas pipelines. Aiming at the accuracy problem of automatic identification of test piles, based on the analysis of the background and target characteristics of the test piles and surrounding objects, a deep learning algorithm was used to determine whether the test piles were obscured by the surrounding objects. For obstructed test piles, the relative location algorithm of the insignificant target was used to detect the specific position of the test piles. Finally, the validity of the algorithm in this paper is verified by actual test scenarios experiments.