Abstract: The aim of the research of user interface is to provide an efficient way of communication between user and computer With the quick development of computer software and hardware and the emergence of Internet, the traditional CAD system user interface faces new challenges In this paper, stresses are put on the introduction of a multimodal user interface prototype system─FreeVoiceCAD, which is developed on the platform AutoCAD It supports the user’s inputs with several modalities, such as natural speech and pointing The user can not only send speech commands directly to the system, but also give and modify graphics objects’ attributes with the help of pointing The drawing efficiency, usability and naturalness are tested and the existing problems and difficulties are pointed out Finally some key problems are put forward, which need further research and attention