Interfacial behavior of Al and -Al2O3 are investigated via molecular dynamic simulation (MD) employing reactive force fields parameterized for Al and Al2O3. The main result of this work is elucidating the wetting behavior and interface chemistry of molten aluminum on the -Alumina (0001) surface through MD simulations. Wetting and interface chemistry are studied at 8 different temperatures from 700 to 1400 K for four different droplet sizes: with 16, 24, 32 and 40 A diameters. Chemical reactions are observed at all temperatures and sizes in addition to diffusion between droplet and substrate atoms into each other during the wetting process. To define the level of wetting, we characterized contact angles of aluminum droplets on alumina substrates for all temperatures and sizes by using a method developed by Hautman and Klein. Chemical reactions are more extensive for the small droplets (16 and 24 A) due to their larger surface to volume ratio in comparison to the larger droplets (32, and 40 A) of droplets.