Sinusoidal　wavy　microchannels　with　secondary　channels　(SWSC)　are　developed　to　integrate　advantages　of　the　sinusoidal　corrugated　structure　and　the　introduction　of　secondary　channels　in　flow　boiling　enhancement.　Flow　boiling　investigations　of　acetone　are　made　with　variation　in　the　heat　flux　and　mass　flux　range　of　251-512　kg/　(m2.s).　The　boiling　curves,　heat　transfer　coefficients,　pressure　drops　and　flow　boiling　instabilities　are　systematically　investigated.　The　experimental　results　show　that　the　SWSC　microchannels　can　achieve　better　heat　removal　performance　than　the　conventional　rectangular　microchannels　(R).　Besides,　the　premature　ONB　and　delayed　CHF　can　also　be　obtained.　The　increased　density　of　bubble　nucleation　induced　by　the　enlarged　surface　area　and　the　liquid　stored　in　the　corner　regions　in　the　nucleate　boiling　dominated　regime,　as　well　as　the　continuously　developing　thin　liquid　film　created　by　the　introduction　of　secondary　channels　in　the　stable　liquid　film　evaporation　dominated　regime　are　considered　to　be　the　main　reasons　for　the　notable　enhancement　in　heat　transfer.　However,　the　SWSC　microchannels　suffer　a　higher　pressure　drop　penalty.　The　pressure　fluctuations　and　temperature　fluctuations　of　the　SWSC　microchannels　are　also　illustrated.