The　hybrid　method　combining　computational　fluid　dynamics　and　acoustic　analogy　is　used　to　investigate　numerically　the　flow　field　and　sound　field　of　centrifugal　fan　for　air　conditioner.　And　the　mass　flow　rate　and　noise　of　centrifugal　fan　are　measured　experimentally,　which　verifies　the　validity　of　the　computational　model　and　numerical　method.　As　for　the　unconventional　volute　used　in　the　original　fan,　the　middle　section　profile　of　the　volute　is　extracted　to　restructure　the　volute　shape　with　straight　tongue.　And　then,　three　kinds　of　volutes　with　inclined　volute　tongue　are　designed.　Based　on　the　numerical　simulation　and　experimental　measurement,　an　optimal　inclined　volute　tongue　is　obtained.　The　experimental　results　show　that　the　aerodynamic　performance　of　the　fan　is　improved　under　all　working　conditions.　The　maximum　flow　rate　is　increased　by　6.0%　and　the　noise　is　reduced　by　1.4　dB(A).　The　numerical　analysis　of　internal　flow　and　sound　characteristics　for　the　optimal　fan　demonstrates　that　the　intensity　and　vorticity　near　the　volute　tongue　are　obviously　weakened.　The　power　spectral　density　and　the　sound　peak　at　the　blade　passage　frequency　are　reduced,　which　indicates　that　the　aerodynamic　noise　of　the　fan　is　effectively　suppressed.　©　2020,　Science　Press.　All　right　reserved.