Influences　of　solution　treatment　on　microstructure　and　mechanical　properties　of　7021　aluminum　alloy　plate　were　investigated　with　the　help　of　microstructure　observation　and　tensile　testing.　The　results　reveal　that　with　the　increase　of　solution　temperature　and　holding　time,　the　undissolved　particles　are　dissolved　gradually　in　the　alloy　matrix.　After　artificial　aging　at　120℃　for　24h,　the　strength　of　7021　is　enhanced　increasingly.　With　the　solid　solution　treatment　at　380℃　for　40min,　the　strength　of　7021　alloy　reaches　the　maxium　value.　With　the　further　increase　of　the　solution　temperature　or　time,　fiber　tissue　in　the　alloy　is　recrystallized,　so　the　grain　is　grown　continuously,　resulting　in　the　decrease　of　strength　and　the　increase　of　elongation.　The　optimum　solution　treatment　for　7021　alloy　plate　is　at　380℃　for　40min.　©　2016,　Journal　Office　of　Special　Casting　and　Nonferrous　Alloys.　All　right　reserved.