The　electron　transport　properties　of　various　molecular　junctions　based　on　the　thiol-ended　oligosilane　are　investigated　through　density　functional　theory　combined　with　non-equilibrium　Green＇s　function　formalism.　Our　calculations　show　that　oligosilanes　doped　by　the　phenyl　and　-C10H6　groups　demonstrate　better　rectifying　effect　and　their　rectification　ratios　are　up　to　15.41　and　65.13　for　their　molecular　junctions.　The　current-voltage　(I-V)　curves　of　all　the　Au/modified　oligosilane/Au　systems　in　this　work　are　illustrated　by　frontier　molecular　orbitals,　transmission　spectra　and　density　of　states　under　zero　bias.　And　their　rectifying　behaviors　are　analyzed　through　transmission　spectra.