Development of electrical industry makes many kinds of electromagnetic pollution in living environment.In order to explore the biological effects and mechanisms of the static magnetic field (SMF),Fourier transform infrared spectroscopy (FTIR) analysis method is used to study changes in brain tissue of rat brain exposed to SMF (0.17 T) for 30 days in the experiment.Experiment shows that the absorption peak of amide Ⅱ near 1549 cm-1 has a significant red-shift,peak position of amide Ⅰ near 1635 cm-1 has a great difference.Differences of molecular structure between the experiment group and the sample group are also analyzed via the second derivative spectra.These results can reflect changes of function and composition in rat brain which is exposed to SMF.Results of this study also indicate that the method of FTIR is an effective means to study the biological effects of electromagnetic field.