The invention discloses a ground marking method for eliminating time drift of a crystal oscillator and relates to the field of detection in pipelines. The method comprises the following steps of: coding ground markers before an internal detector is sent into a pipeline; performing time synchronization on the internal detector and the ground markers through a master clock; sending the internal detector into the pipeline for operation; placing the ground markers on ground marking piles; starting the ground markers to acquire data when the internal detector is close to the ground markers; recording the time when the internal detector passes through the ground markers; storing the recorded time when the internal detector passes through the ground markers into the ground markers; taking the internal detector out of the pipeline, and calibrating each ground marker for the second time; and transmitting the internal detector passing time recorded by the ground markers and data recorded by theinternal detector to a supervisory computer for processing so as to realize the positioning of pipeline defects. By the method, the influence of clock drift is effectively eliminated, the detection precision of the ground markers is improved, and the positions of the pipeline defects are accurately positioned.