Abstract: Objective: Establishing new method for the determination of chlorophenols(CPs).Studying the association reaction mechanism of CPs with HSA. Methods: The affecting factors on the strength of fluorescence quenching including acidity,dosage,temperature and reaction time etc were investigated.According to Stern-Volmer equation,the quenching constant of the reaction and the basic thermodynamic parameters of the blinding process were obtained. Results: The detection limit was 2.26×10^-10 g/mL and the linearity range were 0.75～6.50 μg/10 mL.The fluorescence quenching constant K_q was 3.713×10¹³ L/(mol·s). Conclusion: When the proposed method was used to determine CPs (2,4-DCP) in water,combined with solid phase extractor(SPE),the satisfactory results were obtained and the relative standard deviation was less than 2.91% and the recovery range was 96.44%～105.94%.Fluorescence quenching mechanism of 2,4-DCP with HSA was a static quenching procedure.