The　Al-doped　Mg　2　Si　thin　films　were　fabricated　by　two-target　alternative　magnetron　sputtering　technique,　and　the　influences　of　different　Al　doping　contents　on　the　thermoelectric　properties　of　Al-doped　Mg　2　Si　thin　films　were　investigated.　The　compositions,　crystal　structures,　electronic　transport　properties　and　thermoelectric　properties　of　the　thin　films　were　examined　using　energy　dispersive　X-ray　spectroscopy　(EDS),　X-ray　diffraction　(XRD),　Hall　coefficient　measurement　and　Seebeck　coefficient　measurement　system,　respectively.　The　EDS　results　show　that　the　thin　films　doped　with　Al　target　sputtering　power　of　30　W,　60　W　and　90　W　have　the　Al　content　of　0.68　at.%,　1.56　at.%　and　2.85　at.%,　respectively.　XRD　results　indicate　that　the　diffraction　peaks　of　Mg　2　Si　become　stronger　with　increasing　Al　dopant.　The　results　of　Hall　coefficient　measurement　and　Seebeck　coefficient　measurement　system　reveal　that　all　the　samples　are　n-type.　The　conductivities　of　Al-doped　Mg　2　Si　thin　films　are　significantly　greater　than　that　of　undoped　Mg　2　Si　thin　film,　and　increase　with　increasing　Al　doping　content.　With　the　increase　of　temperature,　the　absolute　value　of　the　Seebeck　coefficients　of　Mg　2　Si　base　thin　films　increase　firstly　and　then　decrease.　The　maximum　power　factor　obtained　is　3.8　mW　m　-1　k　-2　for　1.56　at.%　Al-doped　Mg　2　Si　thin　film　at　573　K.　©　2016　Elsevier　B.V.　All　rights　reserved.