The　silicon　long-diamond　shaped　micro　pin　fin　was　manufactured,　and　the　flow　and　heat　transfer　characteristics　of　long-diamond　shaped　micro　pin　fin　were　experimentally　researched　and　numerically　simulated.　The　results　show　that　within　the　range　of　Re　used　in　experiments,　the　heat　transfer　coefficient　of　the　long-diamond　shaped　micro　pin　fin　increases　with　the　increase　of　Re.　For　the　same　Reynolds　number,　the　heat　flux　has　no　effect　on　heat　transfer　coefficient.　The　thermal　resistance　will　decrease　with　the　pump　power　increasing,　and　decrease　faster　when　pump　power　is　small.　When　the　pump　power　increases　to　a　certain　value,　the　thermal　resistance　will　remain　unchanged.　There　is　no　difference　in　total　thermal　resistance　for　different　heat　fluxes.　Nu　increases　with　the　increase　of　Re.　For　the　diamond　shaped　circular　micro　pin　fin　with　the　same　size,　45°　long-diamond　micro　pin　fin　has　the　best　heat　transfer　performance.　The　long-diamond　design　can　avoid　the　vortex　shedding　which　causes　the　pressure　loss.　Also,　the　long-diamond　design　can　extend　the　heat　transfer　area　and　improve　the　conductivity　of　solid.　Therefore　it　can　enhance　the　heat　transfer　effect.