NUI(Natural User Interfaces) has been developed through CLI(Command Line Interfaces) and GUI(Graphical User Interfaces). NUI uses many different input modalities, including multi-touch, motion tracking, voice and stylus. In order to adopt NUI to legacy GUI applications, he/she must add device libraries, modify relevant source code and debug it. In this paper, we propose a gesture-based interface model that can be applied without modification of the existing event-based GUI applications and also present the XML schema for the specification of the model proposed. This paper shows a method of using the proposed model through a prototype.