||In the field of architectural design, “visualization¨ generally refers to some media, communicating and representing the idea of designers, such as ordinary drafts, maps, perspectives, photos and physical models, etc. (Rahman, 1992; Susan, 2000). The main reason why we adopt visualization is that it enables us to understand clearly and to control complicated procedures (Gombrich, 1990). Secondly, the way we get design knowledge is more from the published visualized images and less from personal experiences (Evans, 1989). Thus the importance of the representation of visualization is manifested.Due to the developments of computer technology in recent years, various computer aided design system are invented and used in a great amount, such as image processing, computer graphic, computer modeling/rendering, animation, multimedia, virtual reality and collaboration, etc. (Lawson, 1995; Liu, 1996). The conventional media are greatly replaced by computer media, and the visualization is further brought into the computerized stage. The procedure of visual impact analysis and assessment (VIAA), addressed by Rahman (1992), is renewed and amended for the intervention of computer (Liu, 2000). Based on the procedures above, a great amount of applied researches are proceeded. Therefore it is evident that the computer visualization is helpful to the discussion and evaluation during the design process (Hall, 1988, 1990, 1992, 1995, 1996, 1997, 1998; Liu, 1997; Sasada, 1986, 1988, 1990, 1993, 1997, 1998). In addition to the process of architectural design, the computer visualization is also applied to the subject of construction, which is repeatedly amended and corrected by the images of computer simulation (Liu, 2000). Potier (2000) probes into the contextual research and restoration of historical architecture by the technology of computer simulation before the practical restoration is constructed. In this way he established a communicative mode among archeologists, architects via computer media.In the research of restoration and preservation of historical architecture in Taiwan, many scholars have been devoted into the studies of historical contextual criticism (Shi, 1988, 1990, 1991, 1992, 1995; Fu, 1995, 1997; Chiu, 2000). Clues that accompany the historical contextual criticism (such as oral information, writings, photographs, pictures, etc.) help to explore the construction and the procedure of restoration (Hung, 1995), and serve as an aid to the studies of the usage and durability of the materials in the restoration of historical architecture (Dasser, 1990; Wang, 1998). Many clues are lost, because historical architecture is often age-old (Hung, 1995). Under the circumstance, restoration of historical architecture can only be proceeded by restricted pictures, written data and oral information (Shi, 1989). Therefore, computer simulation is employed by scholars to simulate the condition of historical architecture with restricted information after restoration (Potier, 2000). Yet this is only the early stage of computer-aid restoration. The focus of the paper aims at exploring that whether visual simulation of computer can help to investigate the practice of restoration and the estimation and evaluation after restoration.By exploring the restoration of historical architecture (taking the Gigi Train Station destroyed by the earthquake in last September as the operating example), this study aims to establish a complete work on computer visualization, including the concept of restoration, the practice of restoration, and the estimation and evaluation of restoration.This research is to simulate the process of restoration by computer simulation based on visualized media (restricted pictures, restricted written data and restricted oral information) and the specialized experience of historical architects (Potier, 2000). During the process of practicing, communicates with craftsmen repeatedly with some simulated alternatives, and makes the result as the foundation of evaluating and adjusting the simulating process and outcome. In this way we address a suitable and complete process of computer visualization for historical architecture.The significance of this paper is that we are able to control every detail more exactly, and then prevent possible problems during the process of restoration of historical architecture.