The effect of pipe oil flowing improver on raising water content ratio, increasing discharged water chemical oxygen demand and etching installation of petroleum refinery was analyzed. Based on the requirement of pipe oil flowing improver in refinery, it was necessary to add electric dehydration, chemical oxygen demand and organochlorine content in evaluation method. This paper introduced the detailed experiment procedures. 3 pipe oil flowing improvers including ethylene-vinyl acetate copolymer, alkylphenol ethoxylates and polyoxyethylene polyoxypropylene copolymer were evaluated by this method. Their electric dehydration rate was 89%,75% and 96%, the ratio of biochemical oxygen demand after five days and chemical oxygen demand in discharged water was 0.33, 0.45 and 0.89, and organochlorine content was 0.95%、0.23% and 0.02%. Polyoxyethylene polyoxypropylene copolymer had little affection on oil electric dehydration, chemical oxygen demand and organochlorine content, which met the quality requirement of petroleum refinery.