A simple method of the magnetron sputtering is applied on the surface modification process of the hydrogen storage alloys. Surface doping of La2Mg17 alloy with yttrium-based coatings is illustrated in the research. Some new intermetallics can be formed on the alloys surface via three steps of magnetron sputtering, surface absorption and heat treatment molding. For the hydrogen storage properties, the reversible capacity and cycle stability of the doped sample are all improved, and the hydrogen desorption activation energy is decreased. On the other hand, the surface conditions during the hydrogen absorption and desorption process are also discussed through the SEM, XRD and XPS analyses.