The　intermetallic　compound　(IMC)　at　the　interface　of　Sn3.0Ag0.5Cu/Cu　solder　joints　under　thermal　cycling　was　observed　and　its　mechanical　properties　were　tested,　the　growth　of　intermetallic　compound　and　the　evolution　of　tensile　strength　of　the　joints　were　studied.　The　thermal　cycling　parameters　such　as　holding　time　and　minimum　limit　temperature　were　changed　to　make　comparative　tests.　At　the　same　time,　the　isothermal　aging　test　and　thermal　cycling　test　were　compared　at　the　upper　limit　temperature　of　thermal　cycle.　The　results　show　that　with　the　increasing　of　cycle　period,　the　equivalent　thickness　of　the　interface　intermeallic　compound(IMC)　increases,　and　the　lower　the　minimum　limit　temperature　is,　the　faster　the　growth　rate　of　the　interface　IMC　is,　and　the　tensile　strength　of　the　joints　increases　slightly　and　then　decreases　continuously.　The　growth　rate　of　the　intermetallic　compound　under　isothermal　aging　condition　is　faster　than　that　under　thermal　cycling　condition　with　the　same　upper　limit　temperature　holding　time,　and　the　interfacial　atomic　diffusion　has　been　kept　relatively　fast　in　the　absence　of　low　temperature　process.　©　2018,　Editorial　Office　of　Transactions　of　Materials　and　Heat　Treatment.　All　right　reserved.