Abstract: Shaanxi-Beijing Gas Transmission Pipeline, with 660 mm in diameter and 847. 8 km in total length, was put into operation in September of 1997. The several kilometers of the pipeline was located at the Loess Plateau in the Northwest of China. The serious loess sinking problem produced by the unique geological conditions, which influenced the safety operation of the pipeline. The geological analysis on the harm of loess sinking to the pipeline is performed, including the formation and development mechanism of the loess sinking. According to the analytical results, some protection measures are put forward.