Microchannel　heat　sinks　have　important　applications　in　integrated　circuits,　but　the　current　traditional　long　straight　microchannel　heat　dissipation　process　causes　uneven　temperature　and　low　heat　dissipation　efficiency.　In　this　paper,　a　periodic　split-flow　microstructure　is　designed　and　integrated　with　traditional　microchannels　to　form　a　periodic　split-flow　microchannel　heat　sink.　Numerical　simulation　is　used　to　study　the　influence　of　the　number,　the　arrangement　and　structural　parameters　of　microstructures　in　a　single　microchannel　on　its　thermal　performance.　The　simulation　results　show　that　the　split-flow　microstructure　can　increase　the　heat　exchange　area,　break　the　original　laminar　boundary　layer,　promote　the　mixing　of　cold/hot　coolant,　and　significantly　improve　the　heat　dissipation　performance　of　the　microchannel.　Through　comparative　experiments,　9　groups　are　finally　determined　as　the　optimal　number　of　microstructures　in　a　single　microchannel.　At　a　heat　flux　of　100　W/cm(2),　when　the　coolant　flow　rate　at　the　inlet　is　1.18　m/s,　after　9　groups　of　microstructures　are　added　into　a　single　microchannel,　the　maximum　temperature　drops　by　about　24　K　and　the　thermal　resistance　decreases　by　about　44%.　The　Nusselt　number　is　increased　by　about　124%,　and　the　performance　evaluation　criterion　(PEC)　reaches　1.465.　On　this　basis,　the　microstructure　adopts　a　staggered　gradual　periodic　arrangement　to　avoid　the　long-distance　non-microstructure　section　between　the　two　groups　of　microstructures.　The　turbulence　element　that　gradually　widens　along　the　flow　direction　makes　the　coolant　fully　utilized.　This　results　in　a　reduction　in　the　high/low　temperature　zone　and　alleviates　the　temperature　gradient　that　exists　along　the　flow　direction　of　the　heat　dissipation　surface,　and　the　pressure　drop　loss　is　also　reduced　to　a　certain　extent　compared　with　the　pressure　drop　in　the　uniform　arrangement,　and　the　comprehensive　thermal　performance　is　further　improved.　It　shows　broad　application　prospects　in　the　field　of　high-power　integrated　circuits　and　electronic　cooling.