In our studied phosphating system, the morphology, chemical composition, phase and corrosion resistance of the phosphate film were characterized by EDS, AES, XRD and cathodic polarization curves. Test results indicated that the phosphate coating was made of the two kinds of Zn3(PO4)2•4H2O and Fe2Zn(PO4)2•4H2O crystals composed. On this basis, we came up the film-forming mechanism of low temperature phosphating technology.