The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable.The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ.The quenching was static quenching,epicatechin had a weak interaction with BSA and the binding site was one.The total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions,avoiding complicated pretreatment and simplify experimental procedure. The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix (EEM) fluorescence. The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable. The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ. quenching was static quenching, epicatechin had a weak interaction with BSA and the binding site was one. total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated the the method exploited in this article is a helpful tool to investigate complicated interactions, avoiding complicated pretreatment and simplify experimental procedure.