“美麗”與“漂亮”這對近義詞，是現代漢語中極常用的語彙，就語感而言我們很難具體說明“美麗”與“漂亮”詞義上的差異，這種現象對於母語非漢語，正學習漢語而尚未建立語感的學生是一個極大的困惑。本文嘗試藉由語義與語法規則、語彙結構之間存在的對應關係，透過資料庫，觀察“美麗”和“漂亮”實際運用的狀況，考察此二詞項句法行為的變化，語法標記的設立，語彙搭配選擇等異同，逆向反推，試圖找出能夠區辨“美麗”和“漂亮”的基本語義特徵，以解釋語法現象背後的成因與規律，及詞彙搭配上的語義條件。本研究總結歸納出三項足以區辨“美麗”與“漂亮”的基本語義特徵，第一是程度是否連續〈+-CONTINUOUS〉，第二是狀態有無變化〈+-CHANGE-OF-STATE〉，第三是行動能否控制〈+-CONTROL〉。冀能“知其然”，更精確地掌握詞的意義和用法，又能“知其所以然”，明瞭差異的原由與理據，若能類推運用於其他近義詞之區辨，必能為漢語教學樹植更堅實的理論基礎。

“美麗” and “漂亮” are a pair of commonly used synonyms in the modern Chinese language. It is difficult to distinguish between their semantics and the linguistic feeling. Their similarity in semantics may cause great confusion to people coming from another culture; since they do not have the benefit of the same lexical intuition as a native speaker. By investigating the relationship between semantics, grammatical rules and lexical structures, and by studying many situations where the two words are used, this essay tries to find out the proper usage of “美麗” and “漂亮”. Three criteria are proposed to determine their differences -- continuity, change-of-state and control. After knowing their semantic differences and understanding the origins, we might be able to establish similar rules for other synonyms in Chinese.