Abstract: This paper discusses the water quality of oily watertreatment system in Henan oilfield and the standards ofinjection water quality. As to heavy oil oily watertreatment, improvements on the technological processmainly include restoring automatic control system,realizingautomatic dividing of the main and auxiliary flowsheets,and guaranteeing water quality, as to light oil oily watertreatment, they include strenthening the application ofautomatic control technique, realizing automatic operationand improving water quality. Meanwhile much efforts havebeen put on experimental study of polymer flooding oilywater treatment and on the deployment of concentratedadditives. The oily water treatment system in Henan oilfieldis basically perfect now after 20 years construction.