High-quality　In0.3Ga0.7As　films　have　been　epitaxially　grown　on　Si　(111)　substrate　by　inserting　an　InxGa1　(-)　As-x　interlayer　with　various　In　compositions　by　molecular　beam　epitaxy.　The　effect　of　InxGa1　(-)　As-x　interlayer　on　the　surface　morphology　and　structural　properties　of　In0.3Ga0.7As　films　is　studied　in　detail.　It　reveals　that　In0.3Ga0.7As　films　grown　at　appropriate　In　composition　in　InxGa1　(-)　As-x　interlayer　exhibit　smooth　surface　with　a　surface　rootmean-square　roughness　of　1.7　nm;　while　In0.3Ga0.7As　films　grown　at　different　In　composition　of　InxGa1　(-)　As-x　interlayer　show　poorer　properties.　This　work　demonstrates　a　simple　but　effective　method　to　grow　high-quality　In0.3Ga0.7As　epilayers　on　Si　substrates,　and　brings　up　a　broad　prospect　for　the　application　of　InGaAs-based　optoelectronic　devices　on　Si　substrates.　(C)　2015　Elsevier　B.V.　All　rights　reserved.