Abstract: Of several commonly used commercial pour point depressants, the GY3 is selected to treat Xifeng crude oil in Changqing Oilfield and optimal technological parameters of treating are established.Doping 10 mg/kg of GY3 and heating the crude to 60℃ lead to depression of its pour point from 18℃ to 4℃ and of its abnormal point from 26℃ to 18℃ and to notable decrease of its apparent viscosity at low temperature.Rheological properties of the crude doped at low temperatures can be deteriorated by repeated heating at < 50℃, but can not be influenced largely by intensive shear.