The main objective of this study is to analyse the information flows and representations which is shown at the displays of the user-OPACs interfaces in the 5 academic library automation systems. The findings made in the study are summarized as follows: 1) The interactive styles of that displays are based on the menu selection style. 2) The structures of information flow on that displays are the compound structure which is basically made of the network, the binary, and the pop-up structures. 3) The elements of the displays are consisted with the fields concerning the database name, the current working area, the indicator, the menu, the exit, the prompt and the system message. 4) The essential entries of the main menus are Book, Periodical. and Thesis. 5) The important languages of the command language styles are Search, Display, Print, Help, and End. 6) The elements of the display structures for the retrieval are the retrieving key, the Boolean operators, and the exit. 7) The major retrieving keys are Title, Author, Subject name, Call Number, and Publisher. 8) The marks of Boolean operators on the retrieval displays is different among the systems each other.