Abstract: Contaminated volume produced is a common phenomenon in batch transportation process ofSouthwestern Products Oil Pipeline.To accurately calculate the contaminated volume, comparison tocommon calculation methods are carried out aiming at selecting an available one which is suitable for thePipeline.The equivalent length of contamination applied to the reducing pipe and variable flow rate sectionis introduced during calculation process.It is pointed out that the calculation results for every intermediatestation greatly differ from field data, which need to be further investigated and analyzed.