一、後面接的詞性不一樣1、keep on後面接動名詞She kept on working although she was tired.她雖疲勞但仍繼續工作.2、keep up後面接名詞例句： The enemy kept up their bombardment day and night.敵軍一直日夜不停地狂轟濫炸.二、意思不一樣1、keep up: 保持,繼續,維持例句：You"re all doing a splendid job; keep up the good work! 你們幹得都很出色, 要保持下去! 2、keep on: 繼續進行(接連,反覆,繼續)例句：She kept on working although she was tired.她雖疲勞但仍繼續工作。三、都指保持時，保持的連續性不同1、keep on 是中間間斷後又繼續做 ；或者堅持這條路？例句：I keep up correspondence with my college friends.我一直跟我大學時代的朋友通訊。