[Objective] The physiological effect of rare earth element (REE) on microorganism resistance, growth and its mechanism were studied in this work. [Methods] The effects of REE on resistance and growth of Bacillus cereus were investigated through inhibition zone method and photoelectric turbidimetry method, respectively, fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy were used to examine the change in structure of cell wall and nucleic acid (DNA). [Results] Resistance of bacteria to 9% Carbolic acid, 0.135% HgCl2 and 8×105 U/mL Penicillin enhanced by 40?50 mg/L La(NO3)3, meanwhile, resistance to 9% Carbolic acid, 0.135% HgCl2, 8×105 U/mL Penicillin and 75% NaClO3 enhanced by 40?50 mg/L Ce(NO3)3. Fission of bacteria could be faster due to tremeant of REE, effect of more La(NO3)3 or Ce(NO3)3 was better than less them. The structure changes of peptidoglycan characterized by FTIR indicated the effect of La(NO3)3 and Ce(NO3)3 on cell wall. Therefore, modification of resistance was considered related to it. The structure of DNA coubld be affected by REE througth fluorescence spectroscopy. [Conclusion] The change of DNA structure was the basic cause that effect on resistance and growth of REE.