Wire　arc　additive　manufacturing　(WAAM)　has　become　a　promising　metal　3D　printing　technology　due　to　its　high　efficiency　and　low　cost.　Process　planning　is　a　critical　step　in　WAAM　that　influences　the　process　output　attributes　in　terms　of　surface　accuracy,　deposition　rate,　and　material　utilization.　Generally,　traditional　methods　are　only　able　to　satisfy　the　variation　of　bead　width,　regardless　of　the　control　on　bead　height,　which　may　not　obtain　the　optimal　process　output　attributes.　To　solve　this　issue,　a　unit　block-based　process　planning　strategy　is　proposed,　which　aims　at　slicing　the　complex　component　into　parallel　layers　with　uneven　layer　thickness.　A　unit　block　is　defined　as　the　deposited　block　per　unit　time,　whose　dimensions　can　be　controlled　by　varying　the　process　parameters.　Once　the　part＇s　3D　model　as　well　as　the　optimization　criteria　is　given,　the　best　unit　blocks　that　fit　this　3D　model　are　determined　and　so　are　the　process　parameters.　This　enables　to　generate　varying　process　parameters　subjected　to　the　part＇s　geometrical　features　and　ultimately　the　optimal　process　output　that　balances　surface　accuracy,　deposition　rate,　and　material　utilization.　The　case　study　for　an　aerospace　component　proves　that　the　proposed　method　is　capable　of　improving　the　surface　waviness　by　46.2%　and　effective　deposition　rate　by　65.6%　as　well　as　the　material　utilization　by　4.2%　with　block　unit　width　of　6　mm.