Three　drop-shaped　micro　pin-fin　heat　sinks　with　different　tail　angles　were　designed　based　on　the　optimization　of　traditional　round　micro　pin-fin　heat　sink.　The　flow　resistance　and　heat　transfer　characteristics　of　the　heat　sinks　were　experimentally　investigated　using　deionized　water　as　working　fluid.　The　results　show　that　the　micro　pin-fin　with　tail　angle　of　60°　has　the　lowest　flow　resistance　among　the　heat　sinks.　The　streamlined　structure　of　drop-shaped　micro　pin-fins　improves　the　distribution　of　flow　and　delays　the　conversion　from　laminar　to　turbulent　flow.　The　smaller　the　angle,　the　more　obvious　the　effect.　The　optimal　angle　of　drop-shaped　micro　pin-fin　is　different　under　different　flow　rates.　The　heat　sink　with　tail　angle　of　60°　has　the　strongest　heat　transfer　coefficient　at　the　corresponding　Reynolds　number　in　this　experiment　(Reynolds　number　is　equal　to　200-1　000).　When　the　tail　angle　decreases　to　30°,　the　heat　transfer　is　also　enhanced　in　the　tail　section　of　micro　pin-fin.　However,　the　flow　is　affected　by　the　micro　pin-fin　behind,　so　the　heat　resistance　is　higher　than　other　heat　sinks　under　the　same　pump　power.