数字化方式是传播遗产价值的重要手段之一，长城作为世界上最大的线型文化遗产具有独特的历史、艺术和科学价值。在文化遗产数字化保护的长期发展中，以往人们较多关注考古器物、字画、文稿等可移动文物和大型佛龛、壁画等不可移动文物领域的数字化修复，但是对长城遗址的数字化修复研究极少。本文立足于数字化修复中多源证据的重要性，结合长城的原貌价值及真实性保护理念，总结了长城数字化修复的基本概念；提出了从领域知识构建、证据转化、证据融合、语义建模到知识服务整个过程的长城数字化修复总体思路，并分析了面临的3个基本问题，包含长城认知、数据采集及证据转化、复原理念及实现问题；继而从长城领域知识构建、数字化修复关键技术和面向需求的知识服务3方面阐述了长城数字化修复的研究方向与重点；最后以九眼楼为例，介绍了数字化修复框架下的修复成果。

Digitization is one of the most important means of spreading heritage values. Nowadays, as one of the symbols of ancient civilization, the Great Wall of China has a great and irreplaceable historical research value, especially in military architecture, technology, and art. In the long-term development of the digital protection of cultural heritage, people have been paying more attention to the digital restoration of movable cultural relics, such as artifacts, calligraphy, painting, manuscripts, and immovable cultural relics, including large Buddhist shrines and murals. However, studies on the digital restoration of the Great Wall ruins remain scant.On the basis of the value demand of the Great Wall protection and the research foundation of digital restoration, this study argues that authentic evidence is the key factor affecting scientific restoration and puts forward the criterion that the digital restoration of the Great Wall should be consistent with the “original appearance” and “authenticity” of the Great Wall. This paper summarizes the basic concepts of the digital restoration of the Great Wall and puts forward the general ideas of the Great Wall digital restoration in terms of domain knowledge, evidence transformation, evidence fusion, semantic modeling to knowledge service. This paper also discusses the three basic problems of the digital restoration of the Great Wall, namely, the cognition of the Great Wall, data collection, evidence conversion, and the concept and implementation of restoration. Aiming at these basic problems, three research directions are proposed, that is, knowledge construction in the field of Great Wall digital restoration, key technologies of digital restoration, and knowledge service. The construction of the knowledge of the Great Wall deepens the cognitive category of the Great Wall. The key technologies are the implementation of spatial geographic information 3S technology, deep learning, and semantic modeling. The knowledge service of the digital restoration of the Great Wall can provide services for the sustainable preventive protection of the Great Wall, experts, and the public. Finally, taking Nine Eyes Watchtower an example, the restoration results under the framework of digital restoration are introduced.The results of the digital restoration of the Great Wall are not absolute. Its greatest advantage is that it can accept the public's judgment and the emergence of new evidence at any time, rendering the digital restoration of the Great Wall as a dynamic and open research process. The significance lies in the integration of multi-disciplinary advantages, showing the restoration process of the Great Wall to different groups, such as departments, experts and scholars, and the public; Furthermore, from the perspective of the protection of the Great Wall, digital restoration is a supplement to the strategy of “original site protection and original state protection,” respecting physical protection and giving full play to the advantages of digital means. The digital restoration framework can not only provide a scientific, humanistic, and feasible scheme for the digital restoration of the Great Wall, but also provide a new reference for the restoration of other ancient sites.