Petrochemical wastewater is of huge quantity released during the production and complicated contaminants of petrochemical wastewater will have immense negative impact on ecology environment Three-dimensional excitation-emission matrix fluorescence(3D-EEM) was used to investigate the characteristic fluorescence of influent and effluent from each processing unit of Hydrolysis-acidification +A/O+ Contact-oxidation Process in a typical petrochemical wastewater treatment plant  The results showed that there were 4 fluorescence peaks named Peak A, Peak B, Peak D, Peak E in the spectrum chart of influent, they are around λex/λem=220/300, 225/340, 270/300, 275/340 nm, the primary source of fluorescence organic matter(FOM) is industrial wastewater The fluorescence intensity of each fluorescence peak was decreased, while location was unchanged in the effluent of Hydrolysis-acidification Peak C appeared from the effluent of anaerobic tank at λex/λem=250/425 nm, then the fluorescence intensity of Peak C was enhanced in the effluent of aerobic tank Peak A disappeared from the effluent of secondary sedimentation tank The spectrum chart of the wastewater had no obvious variation after secondary sedimentation tank The removal rate of FOM was expressed with the degradation percentage of the fluorescence intensity, the total FOM was reduced by 920% after processing, and the removal rate of the FOM fluoresce around Peak A, Peak B, Peak D, Peak E were 1000%, 912%, 803%, 920% respectively A volatile IPeak B/IPeak E value of influent but a relatively stable value of effluent demonstrated that the wastewater treatment plant operated steadily and the process has higher capacity in resistance to shock loading