The interaction between tetrasulfonated zinc phthalocyanine（ZnPcPS4） and albumin（BSA and HSA） was studied by fluorescence spectroscopy.The results showed that albumin had a significant effect on the existing state of ZnPcPS4,and there was a strong interaction between ZnPcPS4 and albumin with a binding constant about 106 orders of magnitude.The competitive binding experiment showed that the binding site for the interaction was mainly located at subdomain IB of BSA.The ZnPcPS4-BSA and ZnPcPS4-HSA complexes were further prepared by a molar ratio of phthalocyanine to albumin about 1∶1.Spectroscopic studies showed that the complexes exhibited a more prominent monomer absorption peak than free phthalocyanine,and the Q-band maximum had a red shift from 692 nm to 696 nm,which was beneficial to photodynamic therapy.Photodynamic anticancer activity test showed that ZnPcPS4-BSA had a high photodynamic anticancer activity with an IC50 value as low as 1.68 μmol/L,which was significantly higher than that of the corresponding free phthalocyanine ZnPcPS4（IC50=2.73 μmol/L）.This could be attributed to the fact that the complexes have a higher cellular uptake toward cancer.