<正> The mechanisms of excitation energy transfer within allophycocyanin monomer with the theory of generalized master equation (GME) and the technique of time-resolved fluorescence anisotropic spectroscopy are studied. In the case of known information of its structure and spectra, the theory applied is based on the assumption that the coupling interaction between two chromophores is fairly weak. The theory correctly predicts the experimentlly observed rate for excitation energy transfer in allophycocyanin monomer. Based on the results, the energy transfer mechanism can be described as Frster and these processes cannot take place from the high vibrational levels of donor to acceptor.