Abstract: In this paper, we have studied the mechanism of intermolecular energy transfer of Rh6G and Cresyl Violet which form a donor-acceptor pair in mixture solution. The relationship between the fluorescence intensity of Cresyl Violet and its concentration has been emphatically studied. The effect of self-absorption of Cresyl Violet upon the fluorescence intensity is appreciable and can not be ignored, as the concentration of Cresyl Violet being high. Considering the effect of self-absorption, we have mo-dified the theoretical formula obtained by Birks, and deduced the relative expressions of acceptor fluorescence intensity and acceptor concentration for both radiative transfer and Forster transfer processes.