Microstructures,　θ(Al2Cu)　phase,　pores,　and　mechanical　properties　of　ZL205A　aluminium　alloy　with　as-cast,　solutioned　and　aged　treated　were　studied　by　means　of　scanning　electron　microscopy　and　X-ray　microscopy.　The　results　show　that　all　ZL205A　specimens　are　consisted　of　block-shaped　α-Al　and　θ　phase　precipitated　among　the　grain　boundaries,　along　with　irregular　pores.　With　aging　time　increasing,　the　size　of　α-Al　grains　increases　gradually　and　then　deceases,　θ　phase　has　no　obvious　variation,　and　the　number　of　pores　firstly　decreases　and　then　increases.　Consequently,　mechanical　properties,　including　tensile　strength　and　microhardness,　increases　then　slightly　deteriorates.　When　aging　for　8　h,　excellent　mechanical　properties　are　obtained　due　to　the　combined　effects　of　grain　refine　strengthening　and　dispersion　strengthening,　such　as　the　refined　α-Al　grains,　the　dot-like　and　short　bar-like　θ　phase　with　dispersive-distribution,　and　the　lowest　porosity.　©　2019,　Editorial　Office　of　＂Jinshu　Rechuli＂.　All　right　reserved.