Pin-through-hole　(PTH)　connection　is　one　of　the　most　common　types　of　connection　between　components　and　circuit　board.　Taking　the　printed　circuit　board　(PCB)　of　the　typical　electronic　product　air　conditioner　as　research　object,　thermal　fatigue　behavior　and　failure　mechanism　of　the　through-hole　solder　joints　were　investigated　by　accelerated　aging　experiments　and　finite　element　analysis　(FEA).　Results　showed　that,　besides　that　of　the　coefficient　of　thermal　expansion　(CTE)　mismatch　between　the　materials　in　the　solder　joint　assembly,　the　influence　of　solder　joint　structure　and　component　weight　the　pin　supporting　on　the　cumulative　damage　to　solder　joints　were　indispensable.　Compared　with　the　typical　supported-hole　solder　joints,　solder　joints　for　this　paper　were　more　prone　to　the　damage　as　component　pin　peeling　off　solder.　And　fatigue　lives　of　solder　joints　decreased　with　component　weight　increasing.　The　solder　joint　lives　calculated　by　FEA　were　between　1300　similar　to　1600　cycles,　which　agreed　well　with　the　experimental　results.