Different　Si　content　alloys　were　prepared　by　stir　casting　process,　aiming　to　reveal　the　effect　of　Si　content　on　microstructure,　mechanical　properties　and　wear　resistance　of　Al-Si-Cu-Ni-Mg.　The　results　showed　that　with　the　increase　of　Si　content,　the　aspect　ratio　and　average　length　of　eutectic　Si　firstly　increase　and　then　decrease,　and　the　aspect　ratio　and　average　length　of　the　alloy　with　Si　content　of　16　wt.%　were　the　largest,　which　were　8.8　and　24.1　μm,　respectively.　After　520　℃　/6　h　solid　solution+180　℃　/5　h　aging　treatment,　the　morphology　of　the　eutectic　Si　was　changed　from　fibrous　to　spherical,　and　the　angles　of　the　incipient　Si　became　smooth　and　rounded.　Eutectic　Si　aspect　ratio　and　average　length　of　the　alloy　decreased　significantly,　keeping　the　same　trend　as　that　of　the　cast　alloy,　and　the　aspect　ratio　and　average　length　of　the　alloy　with　Si　content　of　16wt.%　were　3.5　and　12.4　μm,　respectively,　and　there　was　no　significant　change　in　the　size　of　incipient　Si.　The　tensile　properties　of　the　as-cast　alloys　gradually　decreased　and　the　hardness　gradually　increased　with　increasing　Si　content.　After　T6　heat　treatment,　the　tensile　properties　and　hardness　of　the　alloys　were　significantly　improved,　maintaining　the　same　trend　as　the　cast　alloys.　With　the　increase　of　Si　content,　the　wear　loss　of　the　alloy　decreases　and　the　wear　resistance　is　improved,　the　alloy　with　Si　content　of　16　wt.%　has　the　least　wear　loss　and　the　best　wear　resistance;　the　wear　resistance　of　the　alloy　decreases　when　the　Si　content　continues　to　increase.　©　2024　Chinese　Mechanical　Engineering　Society.　All　rights　reserved.