Abstract: Lanzhou-Chengdu-Chongqing Products Pipeline was put into operation in 29 September, 2002, with total length of 1250 km, three diameters in 508 mm, 457 mm and 323. 9 mm. This pipeline transports two kinds of gasoline and diesel on the batch transportation way with transportation capacity of 500×10⁴ t/year and reaches the design capacity in 2005. The pipeline has 16 pumping stations, 47 block valve rooms and 15 offtake stations. The pigging operations for the pipeline have been carried out since its commissioning. The pigging results show that mud, sands, rust and welding slag as well as other solid substances are main impurities, which plug the filter, abrade pipeline/equipments and deteriorate the products oil. The experiment and analysis on the origin of foreign substances are made and improvement countermeasures against the impurities are worked out based on the test results.