Since 1990s, many researchers made effort on knowledge sharing and agent communication language (ACL). However, to make ACL development and design more intuitive and friendly, there is still room for improvement. Integrating posture status map (PSM) with motion instructions, this research proposes a script system of 3D software agents. Hence, those users who are not familiar with programming or 3D model can also have their customization of agent scripts. 　　A user-friendly editor with designated motion instructions is created to describe agent behaviors in script form. The script representation is analyzed in modular operating process, with reusable and scalable knowledge of human thinking patterns. To coding agent postures and actions, posture script and action script are designed by rule base. Motion instructions named after human language are developed for easy programming. 　　An instruction execution system is developed to support the agent script executed through a control panel or a software library. Users can rapidly produce software agent with reduced development costs. An example software agent, A-Mu, composed of six components: head, body, left hand, right hand, left foot and right foot, is designed with rotatable axes and flexible/elastic body movements. A reasonable posture table with motions and actions is planned for its operations. Experiments show some desired functionality can be achieved and simplified for users to quickly and easily generate the necessary scripts and control the agent motions effectively. The agent functions will be extended in the near future, especially the interactions with hardware and users.