Abstract:Contact angle, penetration depth and water absorption rate were measured for organic silicone protective performance of mortar of different coating methods, and Fourier transform infrared spectroscopy(FTIR), X ray diffraction(XRD), ultra depth of field microscope, scanning electron microscope(SEM) were used for characterization of chemical structure, mineral composition and microstructure. The results show that the best coating method of organic silicon is one time coating with a dosage of 250g/m2. The mechanism of the interaction between organic silicon and mortar samples is the formation of stable Si—O bonds with characteristic peak of 1037cm-1 by condensation reaction, and the sample surface roughness decreases by organic silicon resin, long chain —R base as hydrophobic is arranged inside the slurry surface and capillary channel to play a protective role.