In recent years, porphyrins and metalloporphyrins have attracted much attention in photodynamic therapy and anticancer, and some have been approved for clinical use. Human serum albumin(HSA) can bind and transport some drug molecules. A detailed study of the binding mechanism of metalloporphyrins and HSA is of great significance in clarifying the action mechanism of porphyrin drugs. This study synthesised three kinds of novel free porphyrins modified with 6-chloronicotinic acid(4, 5, 6) and their Zn complex(4-Zn, 5-Zn, 6-Zn) and characterized by UV-Vis, IR, 1H NMR, elemental analysis, fluorescence spectra and theoretical calculations. The theoretical calculation results showed that the 6-chloronicotinate moieties in the three zinc porphyrins were far away from the porphyrin ring plane. The 4-Zn configuration was more stable than the 5-Zn and 6-Zn configurations with substituents. Under simulated physiological conditions, the bonding modes between three zinc porphyrins and HSA were studied by fluorescence spectra, and the results were calculated according to the Stern-Volmer equation, double-logarithmic equation and Van’t Hoff equation. The experimental results indicated: (1) Three zinc porphyrins could all quench the fluorescence of HSA and the values of Kq calculated by the Stern-Volmer equation were much larger than 2.0×1010 L·mol-1·s-1. Thus the quenching type was static quenching. (2) The binding constants were calculated by a double-logarithmic equation. Except for the 5-Zn at 318 K, other binding constants were all greater than 103 L·mol-1, and the binding sites were close to 1, indicating the formation of a 1∶1 complex. (3) According to the Van’t Hoff equation, the thermodynamic parameters ΔH, ΔS, ΔG were all less than 0, eg. those of 4-Zn were calculated to be ΔH=-123.9 kJ·mol-1, ΔS=-322.9 J·mol-1·K-1, ΔG=-27.7 kJ·mol-1 (298 K), indicating that the reaction process was spontaneous and the predominant forces between zinc porphyrins and HSA were vander waals force and hydrogen bond. The experimental data obtained in this experiment can provide useful information for studying the interaction mechanism between metalloporphyrins and biological small molecules.