Abstract: By adding the mobility improver into crude oil, we are trying to reach the goal of changing the wax crystal form, reducing the temperature and strength of the wax crystal formation network, and thus bringing down the pour point and viscosity of crude oil and improving its mobility at low temperature. C-8361 and C-8806 improvers are dealt with in detail in regards to their respective experimental use on Zhong-Luo line and effects, and a comparison is made between the effects shown in the field and that in lab., which makes the author to conclude that 150ppm is the better quantity to be added so far as the crude oil in Zhong Yuan Oil Field is concerned. Also touched in it are the importance of the stability of the improver, selection of crude oil treatment temperature and the installation of pipe cleaning utilities along the pipeline.