Abstarct: Aluminium oxide nano particle were modified whit the weight of trimetoxyvinyl silane (TMVS) and oleic acid as coupling agent was varied from 0.5 to 9 relative to aluminium oxide nanoparticles surface properties and render them more hydrophobic, surface modified Al2O3 nano particles were characterized using x-ray diffractrometry (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR) and elemental analysis (CHN). Hydrophilic properties of modified Aluminium oxide nano particles by lipophilic experiment,was confirmed. As well as the amount of nano-particles dispersed in a solvent water,ethanol, hexane and acetone was evaluated; and the percentage was calculated. Optimum modifiers oleic acid , tri methoxy vinyl silane and the mixture of oleic acid: tri methoxy vinyl silane was obtained 1% , 3% and 2% respectively.