Growth curve of bacteria treated by the rare earth elements and calmodulin inhibitor (chlorpromazine) was studied, and the effect of REE on calf thymus-DNA and intracellular DNA in bacteria was studied by fluorescence spectrum. The results showed that the logarithmic phase of growth and fission of bacteria can be advanced by REE, so they grew faster than contrast. At the same time, Bacillus subtilis was found bigger by SEM. But growth and fission was inhibited by chlorpromazine, indicating that the mechanism about growth and fission of bacteria by REE was connected with calmodulin inhibitor. Fluorescence of ct-DNA can be enhanced by REE. But intracellular DNA in bacteria was different, it can be enhanced by Ce(NO3)3, quenched by La(NO3)3. so we think that the function of REE to biological materials was very complicated.