Abstract: Mainly introduced three site tests of Zhong-Luo Loop Line with addition.Through thermal and hydraulic calculation, it is proved possible for the operation of this pipeline if heated every two stations.Wax deposit and removal measures are discussed based on the changing rule of equivalent wax deposit thickness (EWDT) in low flowrate pipeline with additive with correlation between EWDT and pipeline thermal conductivity coefficient. The conductivity coefficient decreases with the increase of EWDT.To adopt additive as a treating measure to lower pour point and viscosity, to keep wax deposit at a certain thichness so as to lower the thermal conductivity coefficient, which are considered to be the two basic conditions for maintaining safe and economic operation.The writers introduce the basic principle of economic operation of low flowrate with additive based on the site tests. Different by-pass heating methods can be considered for different seasons so as to save as much fuel as possible, which provides experimental and theoretical basis for the safe and economic transportation adopted in Zhong-Luo and other pipelines with low flowrate.