By measuring the three-dimensional fluorescence spectra of extracellular organic matter (EOM) of microcystis aeruginosa sampled from Taihu Lake and cultured in laboratory during the growth period, the characteristics of three-dimensional fluorescence spectra components of EOM were obtained, and then the dynamic release rules of the EOM of microcystis aeruginosa was studied, and the Pearson correlation analysis method was used to analysis the release correlation between these components and MC-LR in the process of growth. The results show that there are four strong fluorescent peaks in the three-dimensional fluorescence spectrum of EOM, namely A, C, S and T. Fluorescence peaks A and C belonges to the same kind of humus components, while the fluorescence peaks S and T belonges to the same kind of protein components. These two fluorescent components are mainly derived from the same process of growth and metabolism of microcystis aeruginosa, and have basically similar dynamic release laws. During the bloom of mcrocystis aeruginosa in Lake Taihu, the normalized intensity of the fluorescent peaks S, T, A, C of dEOM (dissolved extracellular organic matter)and fluorescent peak D of bEOM (bound extracellular organic matter)can basically reflect the ability of microcystis aeruginosa to release MC-LR in different physiological states and environments. And the normalized fluorescene intensity of the fluorescent peak S、T in dEOM can be selected as an important parameter for the future inversion of MC-LR.