Character agent based Multimodal Presentation Markup Language(MPML) has been developed to increase the efficiency of the presentation using a computer. However, authoring of a presentation by using MPML is not simple because MPML describes only the behavior of the character agent. It describes the presentation background by importing HTML documents. This paper proposes EMPML(Extended MPML) which describes not only the behavior of the character agent but also the presentation background. And an authoring tool for the EMPML has been designed and implemented. By integrating the editing of the presentation background and character agent behavior, the proposed authoring tool supports WYSIWIG(What You See Is What You Get) mode designing. By using the proposed authoring tool, users can make a multimodal presentation without knowing the details of EMPML.