The late Tang tomb M1373, unearthed in November 2022 in Baiyangzhai, Xian City, Shaanxi Province, is a well-preserved late Tang tomb heritage. Its colorful and varied tomb murals are significant for studying the worship, etiquette, music, clothing, art, and other aspects of the late Tang period, especially providing direct materials for studying the transformation of mural styles and themes during the Tang and Song dynasties. However, due to its age, the pigment layer of the mural still exhibits many typical diseases, such as pigment peeling, nail peeling, and mud and water pollution. In addition, subsequent mural removal will bring human intervention to the mural. The above will have a certain impact on the information and value of the mural. For this purpose, in this study, we utilized hyperspectral imaging technology to obtain integrated spectral and special information before uncovering murals. Then, spectral analysis and hyperspectral image processing techniques were used to analyze the surface pigment layer of murals. Taking the music and dance painting as an example, the pigment and craftsmanship of mural painting were studied. The experimental results show that the mural uses traditional mineral pigments such as ochre, earth yellow/mineral yellow, and mineral green for its red, yellow, and green pigments, and when drawing carpet flowers, red and green pigments are heavily diluted and used. In contrast, the use of yellow pigments is not obvious. When drawing murals, ink or a hard pen starts the draft, and red lines outline it. The baseline lines are mostly offset from the surface outline lines, and some areas of the outline lines are severely offset from the baseline lines, indicating certain changes between the start and final drafts. Some areas of the baseline lines are more obvious, while others are unclear. Through hyperspectral image processing methods, it was discovered that the starting lines were hidden beneath the pigment layer surface or lines. Moreover, these murals mainly adopted a distributed non overlapping two-dimensional direct view layout, resulting in a slightly poor spatial stereoscopic sense. However, for multiple locations where the fingers of the musician intersect with the flute, some had adopted a two-dimensional direct view drawing method where the foreground and background patterns do not overlap. In contrast, others have adopted a two-dimensional perspective drawing method where a small amount of foreground and background patterns overlap, indicating that the mural was well laid out before and during painting, and there were no obvious alterations. In addition, some hidden sewage pollution diseases were found in the mural. The above research provides data, research methods, and preliminary conclusions to support the development of on-site protection plans for the mural and subsequent research, protection, and restoration.