Abstract: PPD field test made in Beisantai-Wushihua Oil Pipeline shows the facts that: (1) the SYEP-1 PPD has the excellent performance as an additive of treating Cainan and Huo-Bei-Sha crude oil. While dosage is 400 ppm, treating temperature is 60 ℃, the gel point of Cainan oil is decreased from 21.5℃ to 11℃, 10.5℃ fallen, Huo-Bei-Sha blended oil's gel point falls to 3℃, compared with its 16℃ originally, 13℃ reduced; (2) in winter, heat treatment with PPD in first Beisantai Station, the pipeline can operated with followed heat stations shutdown, Which saves fuel oil and operational cost as well as reducing the operation pressure.