Abstract: The rare earth metal yttrium coordination complex pydaH2)Y2(pydc)4?10H2O was prepared by the reaction of Y(NO3)3 with proton transfer compound (pydaH2)2+(pydc)2-, which was synthesized from 2,6-pyridinedicarboxylic acid (pydcH2) and 2,6-pyridinediamine (pyda) under ultrasonic. The chemical composition, structure and thermal properties of proton transfer complex and metal-organic coordination complex were characterized by elemental analysis, IR, NMR spectra, TGA and DTA. Furthermore, antibacterial activities of ligands and their complexes against Bacillus coli and Staphylococcus aureus were also studied. The results indicated that rare earth metal yttrium coordination complex pydaH2)Y2(pydc)4?10H2O have higher antibacterial activity against Bacillus coli and Staphylococcus aureus than that of its free ligands and proton transfer compound (pydaH2)2+(pydc)2-.