One way to enhance polymer systems properties is to reinforce polymers with fibers, whiskers or particles. The embedding of reinforcement in a matrix to produce composites has been practicized a long time. Improvements in properties can often be found at relatively low filler content. The nanocomposites exhibit superior properties such as enhanced mechanical and thermal properties by combining the properties of organic matrix and the inorganic nano-size filler. For development of plastic nanocomposites with advantageous thermo- mechanical properties two critical factor are generally to be taken into account.These are the proper dispersion of the nanotubes in the matrix and the essential need for the strong interfacial interactions between the nanotubes and functional groups of the polymer molecules. In this study silane based coupling agents have been applied for treatment of the alumina nanotubes, which was then used in the preparation of LLDPE/ alumina nanocomposites. The surface treated nanotubes have been applied for reinforcing polyethylene in 0.5- 8 wt%. The different modified alumina nanotubes were processed to polyethylene in two step: one step rout mixing Al2O3 with compatibilizer and polyethylene in small scale compounding and in the second one by two step route using masterbach of maleic- anhydride grafted polyethylene and organo-Al2O3 nanoparticles by melt-mixing with polyethylene in a conical twin-screw micro-compounder to ashive conducting composites. The surface of Al2O3 were modified by using amino-organofunctional trialkoxysilanes and vinylsilane. Chemisorption of a neutral organofunctional silane will result in the loss of ionizable groups of alumina and hence will lead to a decrease in surface change. The samples prepared were characterized by tensile strength on Instron 5866 and thermal characteristics analysis carried out with a Setaram- Setsyss 1750. The fractured surfaces of the composites have been investigated by SEM indicating strong interaction between the alumina nanotubes and polymer matrix. Moreover, the effect of silane increased dispersing of nanoparticles uniformly throught of polyethylene matrix has allowed the determination of the loss inter- aggregate distance and leads to an inprovement of thermal and mechanical properties of polyethylene-silylated alumina nanocomposites: a significant increase by as much as 400C on thermal stability. Functiozation of the LLDPE matrix lead to better silylated alumina dispersion and improved mechanical properties of nanocomposites. Key words: Polyethylene, alumina oxide, nanocomposites.