This　paper　gives　a　detailed　analysis　and　discussion　of　the　flow　field　inside　the　type　of　D125　MOCVD　reactor　chamber　through　the　analysis　of　three-dimensional　mathematical　model　and　calculation.　Under　a　wide　range　of　geometric　and　process　parameters,　such　as　varying　total　flow　rate　of　gas　inlet,　chamber　pressure,　growth　temperature,　and　wafer　carrier　rotation.　It　is　finally　obtained　the　favorable　conditions　of　the　uniform　distributions　of　velocity　profiles　inside　the　reactor.　The　CFD　simulating　results　are　beneficial　to　fixing　on　the　process　operating　conditions　document.　©　2011　IEEE.