A series of complex such as Eu(α-NMA)₃phen·H₂O were synthesized using the rare earth Eu,the first ligand α-naphthoic acid,β-naphthoic acid,α-naphthaleneacetic acid,β-naphthalene acetic acid and the second ligand 1,10-phenanthroline.The 4 kinds of rare earth complexes were dry white powder,and exhibited good thermal stability.The antibacterial spectrum of the rare earth complexes were detected by the filter paper diffusion method,and the results showed that the antibacterial activity of them to different types of strains was stronger than the pure rare earthions and the ligands,and with broad-spectrum anti-bacterial properties;At the same time,the antibacterial capacity of the rare earth complexes and its ligands were determined by the filter paper diffusion method.And their MIC₁₂ is 43.5 μg/mL,MIB₁₂ is 87 μg/mL.According to the principle that the rare earth elements could send out fluorescence under the UV excitation,a preliminary positioning to the role of cell position was observed by using fluorescence inverted microscope.The rare earth ions,phen and the complexes could damage the shape of the cell by observing with SEM and the rare earth ions and the complexes could also absorb on the cell surface while the phen could not,which was accordance with the result of the fluorescence inverted microscope.The above results indicated that the rare earth may damage the cell surface or the membrane or enzymes and so on.