Magnetic ultrathin films were fabricated layer-by-layer using a serf-assembly method through the electrostatic interaction between the photosensitive diazoresin (DR) and the negatively charged Fe3O4 nanopartides (NP-Fe3O4)．The results of the UV-vis spectra and AFM show that the assembly of DR and NP-Fe3O4 is very Successful．After UV irradiation

the ionic bonds of the DR/NP-Fe3O4 film convert to covalent ones and the magnetic films become very stabletoward polar solvents．The magnetic film images with good resolution are obtained bymeans of selective UV-exposure of the film under a photo-mask and then developing the exposed film in the saturated aqueous solutian of sodium dedecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB)

respectively．