The ultrafast energy transfer has been investigated in a porphyrin (TPP) and polypyridyl ruthenium (Ⅱ) (Ru) hybrid, which is linked by a butyl chain by using time-resolved fluorescence spectroscopic technique. The experimental result shows that，when the excitation wavelength is at the absorption peak (～453 nm) of the Ru moiety，an ultrafast energy transfer occurs from Ru to porphyrin moiety (～400ps). When the excitation wavelength (～400 nm) is at the absorption peak of the TPP moiety，no energy transfer is detected from TPP to Ru. The origin of the energy transfer has been analyzed by using Frster theory. The theoretical result shows that the energy transfer is attributed to dipole-dipole interaction based on the spectra overlap.