Tomb murals, as an important cultural heritage in China, reflecting brilliant civilizations and ancient sciences and technology, as well as advanced social productive forces at that time, are a typical representative of “living” cultural relics. Conservation research and value interpretation of mural cultural relics are an important part of the national cultural confidence construction strategy. Based on the fragility of the materials and low environmental tolerance of tomb murals, the main conservation methods for tomb murals at present are detachment and relocation, which, however, may lead to the loss of some original information. Therefore, it is necessary to establish a system of information extraction methods for tomb murals, to record surface information, extract hidden information and carry out comprehensive research at archaeological excavation sites from the very beginning of work at the site. We referred to the methods for information extraction of grottoes, architectural murals and archaeological sites, combining the characteristics of tomb murals, knowing that the information extraction of tomb murals was not comprehensive and in-depth. We then studied the information extraction methods for tomb murals using several tomb murals in Shaanxi, Sichuan, Jiangxi, Hebei and Ningxia as research objects and thus proposed on-site information excavation methods for tomb murals for the first time. First, means for environmental control were proposed to delay the deterioration of murals according to the environmental monitoring. Second, in combination with photography and spectroscopy, a multi-dimensional image information extraction method was developed to comprehensively and deeply record mural information from macroscopic to microscopic scale, from visible spectral to multi-spectral range. Then, various portable detection devices were used on the premise of scientific selection of interest points, and a research approach was established to effectively obtain the composition of materials and the techniques for making of murals, from surface to inside, from point to area and through focusing on the value of scientific research points. Finally, based on the multiple results above and through observation and instrumental detection, multi-angle and multi-level disease investigations were carried out to obtain the distribution and degree of disease of murals. Moreover, requirements and methods of sampling were proposed for the purpose of research and sample storage. Information extraction of tomb murals at archaeological sites is a key part of on-site conservation and subsequent archaeological research. Large amounts of image resources and data accumulated provide support for mural conservation, important evidence for archaeological research and a scientific basis for exploration of mural value. It has greatly improved archaeologists’ attention to on-site information extraction and promoted interdisciplinary integration. This study makes up for the lack of systematic methods for extraction of information from tomb murals, provides technical support for the development of the industry and plays a role in realizing the effective conservation of mural cultural relics.