Hydrogen can be a main energy resource in near future. Al-Mg-Si-Cu alloys have been used as an inner materials for a high-pressure hydrogen container. There are plenty of studies investigating hydrogen trapping sites in Al alloys, but hydrogen behavior has been still unknown, especially their kinetic properties of atomic states. For safer use of aluminum alloys in hydrogen gas/liquid tanks and other hydrogen atmosphere, we are interested in hydrogen trapped sites in aluminum alloys. For this purpose, we would like to establish a new technique to study the kinetic property of hydrogen atoms in commercial aluminum alloys using a muon spin relaxation method.