Abstract: Generally speaking, an oil pipeline is designed based on the high output of an oil field. Yet slack line operation is often the case during the initial and the late periods of operation. Outgoing flowrate usually gets less and less with the oil field being aging and also refinery operation increasing within the oil field. On top of the above mentioned factors, estimation on oil output is usually higher than it really is, therefore, large diameter pipeline is built. For these reasons, most of the pipelines laid in China are running at a low flowrate.Such critical definition is stated in the paper that "low flowrate" means that the pratical flowrate is higher than the allowable minimum flowrate, "ultralow flowrate" means the practical flowrate is lower than the allowable minimum flowrate. China is rich in highly viscous and easily gelatinated oil. It is neither of economy nor safety to maitain low flowrate transportation. To solve the problem, the following is normally considered convenient abroad; Adding diluent oil or additive for modification so as to make the pipeline maintain shutdown for longer time to obtain an intermittent operation. In China, the research on the process technique-additive addition followed by comprehensive treatrentment has seen its outstanding economic benefit and can be applied in full-line operation as well.