Abstract: Petroleum is a common pollutant in water pollutant control standards. The main methods for determining petroleum in China include gravimetric method, fluorescence spectroscopy, infrared spectrophotometry, ultraviolet spectrophotometry, gas chromatography, etc. Except for the gravimetric method, all the other methods have the problem of reference materials selection and consistency. Using the UV spectrophotometric method, three common, commercially available reference materials A, B and C for petroleum in n-hexane were tested and analyzed, the results of which can be helpful for those engaged in petroleum pollution monitoring.