The fluorescent properties of 22,24-Diprotonated 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrin interacting with the P-sheet structure of a zwitterionic Poly(Glu-Val-Lys-Val) were investigated under various conditions. The TPPS diacid species formed four types of aggregated species by the addition of the polypeptide and/or NaCl. The fluorescent bands were observed for the monomeric and their three aggregated species. The fluorescent intensity changes and maximum wavelength shifts indicated that the monomeric and their aggregated species bound to the polypeptide by electrostatic interaction. The poly(Glu-Val-Lys-Val)/TPPS diacid species system may be provided a good model for studying the porphyrin assembly binding to specific protein domains with definite orientations and alignments.