Wire　and　arc　additive　manufacturing　(WAAM)　has　gained　popularity　in　recent　years　due　to　its　unique　efficiency　and　cost　advantages.　Nevertheless,　due　to　the　stair-stepping　effect　and　the　liquidity　of　molten　metal,　the　achieved　geometric　accuracy　and　surface　quality　are　still　very　limited.　The　combination　of　WAAM　and　machining,　namely　hybrid　manufacturing,　provides　a　fundamental　solution　to　the　above　problem.　Because　machining　is　performed　after　depositing　several　layers,　the　deposition　width,　deposition　height,　and　surface　waviness　have　great　effects　on　the　machined　surface　quality,　in　addition　to　the　machining　parameters　including　spindle　speed　and　feedrate.　In　this　paper,　the　dependence　of　the　machined　surface　quality　(characterized　by　surface　roughness)　on　the　influencing　factors　mentioned　above　is　investigated　based　on　quadratic　general　rotary　unitized　design　(QGRUD).　To　reduce　the　number　of　experiments,　a　comprehensive　factor,　namely　material　removal　area　(MRA),　is　introduced　to　characterize　the　deposition　width,　deposition　height,　and　surface　waviness.　The　analysis　results　show　that　spindle　speed　is　the　most　influential　factor,　followed　by　MRA　and　feedrate.　Furthermore,　a　high　spindle　speed　and　a　moderate　feedrate　are　preferred,　which　contribute　to　not　only　improving　the　surface　quality　and　the　efficiency　but　also　reducing　the　demand　of　geometric　accuracy　for　WAAM.