The time-resolved polarized fluorescence of oriented R-phycoerythrin single crystal from red alga Porphyra yezoensis was studied in picosecond time scale. The fluorescence decay of the crystal exhibited two exponential processes, one of which was related to the energy transfer and excitation equilibrium between chromophores (tau(1)</=60 ps), and the other to the fluorescent transition of chromophores (tau(2) approximate, equals 300 ps). The fluorescence of the crystal was highly depolarized due to excitation transfer between chromophores, and its anisotropic decay was distinctly dependent upon the crystal orientation because of the distribution of chromophore optical transition moments predominantly orienting around the principal axis of the crystal.