We studied the properties of inorganic-organic hybrid coating films prepared by boehmite sol. Sols were synthesized by sol-gel process using nano boehmite and methyltrimethoxysilane in variation with the amount of methyltrimethoxysilane at different reaction time. In order to understand physical and chemical properties of sols prepared from boehmite and methyltrimethoxysilane, coating films were fabricated on glass substrates by dip-coating process. The crystalline pattern and morphology of sol powder of boehmite were observed. Contact angle, surface roughness, transmittance, chemical bond and thermal stability of coating films were investigated.