In this research, the surface of magnesium alloy AZ31 is modified by friction stir processing (FSP). The modification process consists of synthesis AZ31/ZnO composite by establishing holes at surface which are filled with nano ZnO and FSP was carried out at traverse speed 45 mm/ min. and rotational speed of 1100 rpm. Nano ZnO is a biocompatible material and it was used previously for coating AZ31 alloy in lightweight industrial applications. However, the novile surface composite of AZ31/ZnO established in solid-state processing (FSP). The results show that the corrosion product layer has increased passivity at the modified surface which exhibited lower corrosion rate (51%) than that of base alloy AZ31, due to the presence of nano ZnO particles. On the other hand; the hardness increased which can be attributed to the grains refinement (from 15 to 4.3 µm) and the formation of nanocomposite at the surface. The research shows a promise in lab-based studies, that can be a way to manufacture large-scale biomaterials.