Abstract: As one of the most important applications of Computer Aided Architectural Design （CAAD） ，the computer architectural rendering is gradually taking the place of the manual architectural rendering now ．Then how to create the computer architectural rendering more artistically and more intelligently is a significant question for the study in CAAD．In this paper，the tremendous influence in the architectural design and insufficiency of the computer architectural rendering are expounded．Secondly，combining the study of synthesis reasoning，a lot of research instances are illustrated and then the future purpose of the computer architectural rendering is discussed．