The main study of this thesis is of preparing in line with application requirements of nano-Fe3O4 on the magnetic Fe3O4/PVA (polyvinyl alcohol) composite film, the effect of citric acid radical on character of Fe3O4/PVA composite film. Test infrared spectra, magnetic distortion and susceptiveness of Fe3O4/PVA composite film. It shows the Fe3O4/PVA composite film, which prepared by nano-Fe3O4 with adding citric acid radical is good on dispersion but with little magnetic distort energy and susceptiveness.