Spectral sensitization micromechanism of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr microcrystals with different dye concentrations is studied by using picosecond time-resolved fluorescence spectroscopy,and the dependences of electron transfer and spectral efficiency sensitization on different conditions are analysed in detail. With the steady spectroscopy, the wavelengths of absorption and fluorescence of J-aggregate adsorbed on AgBr microcrystals are found to shift to red relative to dye monomer. The spectrum of fluorescence has a red shift relative to the absorption peak. With the time-resolved fluorescence spectroscopy, the fluorescence decay curves of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr grains are found to be fitted well by a double-exponential decay function. The fitting curves consist of a fast and a slow component. Because of the large amplitude of the fast component, this fast decay should be attributable mainly to the electron transfer from J-aggregate of dye to a conduction band of AgBr.