The interface of computer software has to promote human-computer interaction. The one quality of interface to promote HCI should be evaluted with regard to user's information processing. The usability of interface is one of the main components of it's quality, and it is straightforwardly concerned with learnability, especially when users want to use a software at the first stage. In this paper, word processors, wide spreadly used in OA environments is studied in respect to menu structure on the interface. An cognitive menu structure is suggested by user's conceptual network of the main functions of word processor. Two word processors is selected to compare with the cognitive menu structure and to evalute learnabilities by teaming model.