Magnetic tunnel junctions (MTJs) with an L10-ordered FePt alloy were fabricated and characterized. As a bottom electrode, an in-plane magnetized L10 FePt(110) layer was grown epitaxially on an Au buffer layer. A multiple oxidation process was used for the formation of Al oxide barriers. The L10-FePt/AlO/FeCo MTJ prepared shows tunnel magnetoresistance of 18% and 40% at room temperature (RT) and 4.2 K, respectively. The observed RT magnetoresistance is improved, compared to the previously reported results for the L10-FePt MTJs by a conventional single oxidation process.