Teacher authority has long been recognized as one of the critical factors that contribute to the formation of effective learning circumstances (Haywood-Metz, 2006). A survey was developed based on Dornbusch and Scott's (1975) theoretical framework of distinction between formal authority and informal authority, named "The Attitude towards College Instructor Authority" (ACIA). By using this survey among Chinese and American students at an American University, the current study examines college students' perception of instructor authority, including their preference of formal or informal authority, the valued elements in instructor professional competence, as well as the relation between instructor's perceived demographic features and their authority power. The results indicate that overall students rely highly on instructors' position-attached formal authority rather than professionally-oriented informal authority. Whereas there are culture-specified differences between Chinese and American college students' valued dimension of instructors' professional competence at the informal authority level. Possible reasons for the similarities and differences are addressed.