Abstract: He-Shi(Hejian-Shijiazhuang)Oil Pipeline has been operating at low throughput when commissioning since 1993. To solve this problem, the laboratory and site tests adding the CE-H depressant to the oil have been made, and the results show that a obvious effect in pour point depression and viscosity reduction has been obtained when the 50 mg/L of CE-H depressant is added to the oil with a comprehensive treatment at 70 ℃. The freezing point of the crude oil depresses from 36 ℃ to 16 ℃ (the magnitude of pour point depression is 20 ℃), the viscosity depresses from 549 mPa·s to 137 mPa·s (the viscosity reduction rate is 74.9 %). The allowable shut-down time of the pipeline can be extened after the oil is modified, the viscosity reduction effect is better at low temperature. The CE-H depressant also has a better characteristics in anti-shear and reheating. The oil throughput transported can be reduced with the depressant added instead of reverse pumping at when the oil throughput is lower than the minimum initial oil throughput of the pipeline, which realizes the cost-effective and safe operation.