Femtosecond-time-resolved fluorescence spectroscopy technology has been carried out to study the fluorescence spectral properties and energy transfer properties in homotrimer and heterotrimer of the light-harvesting complex Ⅱprepared from Bryopsis corticulans , which is excitated at 495 nm and room temperature . Both homotrimer and heterotrimer have obtained five spectral components by Gauss analysis, and each of which reflects different spectral properties. Furthermore, the fluorescence spectra of the two complexes have been analyzed and compared. In addition, Triexponential time fitting for the fluorescence decay curve of homotrimer yields 3 components lifetimes of 165±8.5 fs, 2.2±0.6 ps and 5.1±0.1 ns, of hetermotrimer receives 3 components lifetimes of 255±6.3 fs, 4±0.8 ps and 3.8±0.1 ns, and all of which have been given ascription. Here, the two shorter time components of homotrimer are faster than those of heterotrimer.Which shows that the protein binding