Abstract: Huoshaoshan——Beisantai Pipeline in eastern Xinjiang, a pipeline transporting viscous and gelatinous crude oil in western China, has been in operation at extra-low throughput all along since its commissioning.While the minimum design throughput is 683 thousand t/a, the actual throughput of the pipeline was only 400 thousand tons in 1992. Low throughput rate of the pipeline restricted the out delivery of crude oil and influenced directly the production of the Huoshaoshan Oilfield. So, based on the properties of Huoshaoshan's crude oil, the crude oil flowability improver of EP series was developed jointly by Xinjiang Petroleum Administrative Bureau and Zhejiang University for the purpose of improving oil rheological behavior at low temperature. The main physical properties of the oil were obtained through laboratory tests and industrial tests at different temperatures and dosages. With 20 ppm improver, the shear stress of the crude decreases by a large margin, and its rheological behavior is very close to Newtonian fluid(its rheological behavior index being 1). With 30 and 50 ppm improver, the viscosity reduction effect is not so obvious as with 20 ppm improver. The paper proves with graphes and data that the flowability improver produces obvious effect on improving the flowability of the crude oil in Xinjiang, and can realize extra-low throughput operation in winter.