A Zn-Pd heterometallic metal-organic framework (MOF) based on 3,5-pyridine-dicarboxylic acid (H2-pydc), namely [Zn2(H2O)3{PdCl2(pydc)2}]n (Zn-Pd-2) was successfully synthesized by a slow diffusion method and characterized by single-crystal X-ray diffraction, CHN elemental analysis, FT-IR spectroscopy, thermogravimetric (TG) analysis and N2 gas adsorption measurement. The single-crystal X-ray analysis revealed that the framework morphology of Zn-Pd-2 is as same as that of [Zn2(DMF)3{PtCl2(pydc)2}]n. The Zn-Pd-2 was found to be an effective catalytic performance for the photochemical reduction of water in a well-known photo-system made up of [Ru(bpy)3Cl2] (bpy = 2,2'-bipyridine), MV(2+) (methyl-viologen) and Na2 EDTA (Disodium ethylenediaminetetraacetate); 20.2 turnover based on Zn-Pd-2 was achieved at 4 h irradiation.