Abstract: Resins and asphaltenes in oily waste water can affect the efficiency of waste water treatment facilities,so it is necessary to determine their contents.In this research,the same separation process with ′four groups′ analysis method was used,but after separation the contents of resins and asphaltenes were determined by ultraviolet spectrophotometry.Several samples of crude oil and oily waste water were tested by using this method,the results agree with the ′four groups′ analysis method very well.This method is faster than the ′four groups′ analysis method and can be used as a control analysis method for a plant.