Effects　of　solution　treatment　on　hardness　and　microstructure　of　semi-solid　squeeze　casting　A319　alloy　were　investigated.　The　characteristics　of　solution　treatment　semi-solid　squeeze　casting　A319　alloy　was　analyzed.　The　results　show　that　compared　with　metallic　mold　casting　A319　alloy,　semi-solid　squeezing　casting　A319　alloy　exhibits　the　features　of　low　segregation　degree　and　high　solidification　rate,　where　eutectic　Al2Cu　phase　is　distributed　along　the　grain　boundary,　and　Q-Al5Cu2Mg8Si6　phase　in　form　of　eutectic　and　fine　strip　is　distributed　in　grain　boundary.　The　metallic　mold　casting　A319　alloy　exhibits　serious　segregation　and　low　solidification　rate,　where　Al2Cu　phase　exists　in　the　grain　boundary　and　the　matrix　in　form　of　block　or　mixed　structure,　and　Q-Al5Cu2Mg8Si6　occurs　in　the　grain　boundary　and　matrix　in　form　of　dense　block　and　rod.　The　morphology　of　phase　contained　Cu　is　inhibited　in　solid　solution　process.　The　phase　contained　Cu　is　more　easily　solved,　so　it　needs　a　short　solid　solution　time,　exhibiting　the　solid　solution　features.　It　is　feasible　for　semi-solid　squeezing　casting　A319　alloy　with　solid　solution　at　505℃　for　3　h.　©,　2015,　Journal　Office　of　Special　Casting　and　Nonferrous　Alloys.　All　right　reserved.