With　the　rapid　development　of　digital　design　methods,　irregular　curved　shapes　have　been　more　and　more　widely　used　in　buildings,　which　not　only　enriches　the　appearances　of　buildings,　but　also　provide　new　possibilities　of　improving　building　performance　by　shape　designs.　However,　existing　researches　regarding　building　performance　and　shapes　mostly　focus　on　regular　shapes,　while　curved　shapes　are　rarely　explored.　This　paper　aims　to　employ　design　optimization　method　to　explore　the　improvement　of　building　performance　that　curved　shapes　could　contribute.　Specifically,　office　buildings　are　chosen　as　an　example　and　the　potential　of　improving　the　daylight　efficiency　of　them　by　optimized　curved　facades　are　investigated.　Three　major　cities　and　two　orientations　are　involved　in　the　investigation.　The　results　prove　that　curved　facades　do　have　significant　potential　to　improve　the　daylight　efficiency　of　office　buildings,　and　an　average　improvement　of　0.2032　is　achieved　by　the　optimized　curved　facades　in　the　6　cases　conducted　in　this　research　in　terms　of　the　area-weighted　average　UDI　(useful　daylight　illuminance)　compared　with　the　same　building　with　plane　facade.　©　2018　and　published　by　the　Association　for　Computer-Aided　Architectural　Design　Research　in　Asia　(CAADRIA)　in　Hong　Kong.