Starting from the idea of academic freedom, this essay discusses the development of American higher education, how academic freedom was originated in the Western civilization, and how the American professors organized the Association of American University Professors(AAUP) for protecting their rights. The essay is divided into four parts:1)the birth of the idea of academic freedom;2)the threats to the academic freedom in history;3)the development and transformation of American higher education; and 4)the establishment and function of the AAUP. The author believes that the freedom of speech and the freedom of research are not taken for granted; instead, they are obtained through the struggles in which numerous scholars and professors had sacrificed their privileges and even their lives. Academic freedom can guarantee the development and growth of educational opportunities on the one hand and enhance the quality of education on the other. Thus, academic freedom deserves protection and defence. The author points out that since the AAUP was established during the First World War period it has become one of the most important organizations to protect academic freedom. But it is not the only purpose of the AAUP to enlarge the professors' rights. As a matter of fact, the AAUP also emphasizes the professors' sense of duty and the importance of their maintainance of pedagogical competence and moral integrity. Finally, the author maintains that there are useful experiences and lessons that the American higher education can provide for the advancement of Taiwan's education. For example, the reluctance of Harvard's employing its graduates and its strong desire to attract the world-wide excellent teachers to work in Harvard should be regarded as a good example for reforming the employment system of Taiwan's universities.