摘要：This paper made a comparison of Cicero’s Rhetoric with baumgarten’s Aesthetics,for answering the question of how baumgarten built the system of ars aesthetica on the basis of Cicero’s *** paper demonstrated how baumgarten’s key ideas of pulchritudo and magnitudo were related with Cicero’s decorum and modus ***’s magnitudo originated in Cicero’s ***,however,differentiated the idea pulchritudo from the Cicero’s decorum for approaching the issue of pulchritudo ipsa.