Abstract: Take Golmud Lhasa product pipeline as an example, the author considers that the contaminated product produced from the transportation distance, shear speed of product, intermediate pumping station, peak point slack flow downstream, shutdown and elevation. It is pointed out that to reduce the contaminated product, some measures, such as batch transporting heavy product behind light product, cutting preducts with ball valve, simplifying the process flow of pumping stations, controlling the inlet pressure of pumping stations behind the peak point slack flow downstream and avoiding shutdown, should be taken, whish can decrease the contaminated product. The process flow of blending contaminated product and blending proportion are introduced.