A new Bi(III) coordination polymer Bi2(Hpdc)2(pdc)2·2H2O (H2pdc=pyridine-2,6-dicarboxylic acid) was synthesized by hydrothermal method. Solid state thermal decomposition of this complex under 500°C for 1h led to the foliated Bi2O3 nanoparticles, which were then characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Comparative study on their photocatalytic activity toward the degradation of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) in polluted water was explored, and the mechanism of these photocatalytic degradation was discussed. These results provided some interesting insights into their photocatalytic applications.