This study investigated pollution source of abnormal influent of a wastewater treatment plant（treatment capacity of 60 000 t/d） in a southern town with the help of the pollution discharge source identification technology based on aqueous fluorescence fingerprint. The comparison results of the aqueous fluorescence fingerprint indicated that the suspected source of the abnormal influent was plastic/rubber industry and the abnormal influent was from underground pipes（P1） of the 10# location in the sewage pipe network， where the chemical oxygen demand of the water sample was 772 mg/L， being higher than the Class III of the Integrated Wastewater Discharge Standard（GB 8978—1996） by 0.54 times. Then， a plastic/rubber enterprise was identified as pollution source based on the high similarity（99%） of aqueous fluorescence fingerprint between the raw wastewater of the enterprise and the sewage from P1， and the high -chemical oxygen demand of the raw wastewater of 11 551 mg/L. Since the water quality of the wastewater from the enterprise’s legal sewage discharge outlet was better than the discharge standard， thus it was clear that the enterprise illegally discharged raw wastewater into the sewage pipe network. It took 5.5 hours to conduct the pollution source identification process. Due to the fast and precise identification， the pollution discharge was timely stopped to avoid further deterioration of influent’s water quality and treatment plant’s operation. This practical research demonstrated that the identification technology can achieve rapid and precise pollution source identification under strong disturbance of complex wastewater.