This article treats a component-based approach for the prototyping of Tai Chi-based physical therapy games. The research group of the authors has already proposed a component-based three-dimensional (3D) software development system called IntelligentBox. One of the application fields of IntelligentBox is the development of 3D games. In this article, the authors validate the availability of IntelligentBox for the prototype development of Tai Chi-based physical therapy games that require several functionalities, for example, body action input, sound play, movie play, and so on. For them, IntelligentBox has already supported a video-based motion input, a motion capture system input, a data-glove input, and so on. Also, physical therapy games need fine-tuning, according to each of the rehabilitants, because their physical disability levels differ. Therefore, therapists have to frequently change many parameters such as a body action speed, difficulty levels of body actions, and so on. For this point, the component-based approach is significant. To validate this, the authors have been developing physical therapy games using IntelligentBox and they have just developed a practical Tai Chi-based dance game as one of the physical therapy games. In this article, the authors explain how easily such a game can be developed using IntelligentBox. The authors also explain new functionalities of several components of IntelligentBox extended for this development. In addition, this article shows the results of the performance evaluations to indicate that the developed game practically can be used as a physical therapy game. The authors also propose another framework enables network collaboration of the developed “Tai Chi” game.