This　paper　conducted　an　experimental　investigation　on　flow　and　heat　transfer　characteristics　associated　with　the　forced　flow　of　de-ionized　water　in　a　periodical　changeable　cross-section　micro-channel　(PCMC)　heat　sink.　The　friction　factor,　Nusselt　number,　average　temperature　of　heating　film　and　thermal　resistance　of　heat　sink　under　different　pump　power　were　obtained.　In　comparison　with　traditional　micro-channels　with　constant　cross-section,　the　periodical　changeable　cross-section　micro-channels　could　produce　higher　heat　transfer　coefficients　and　friction　factors.