The　priduction　of　heat　radiating　shell　of　ultrathin-walled　aluminum　alloy　radio　filter　with　the　heat　sink　in　range　of　0.8-1.0　mm,　was　investigated　by　the　RSF　rapid　slurry　forming　of　semisolid　die　casting　with　the　help　of　the　MAGMA　simulation　software　to　analyze　the　forming　process　of　semisolid　die　casting.　And　influence　of　different　value　of　low/high　injecting　velocity　and　high　speed　switching　positions　on　the　flow　and　filling　of　semi-solid　slurry　was　analyzed.　The　result　reveals　that　with　the　low　in-jucting　velocity　of　0.1　m/s,　the　high　injecting　velocity　of　3.5　m/s　and　the　high　speed　switching　position　of　720　mm,　it　can　be　satisfied　for　the　technical　shaping　requirements　of　the　heat　radiating　shell　of　ultrathin-walled　aluminum　alloy　radio　filter.　And　the　process　parameters　were　verified　by　the　actual　production.　©　2016,　Journal　Office　of　Special　Casting　and　Nonferrous　Alloys.　All　right　reserved.