Spectral analysis is a practical analytical technique suitable for the study of painting. Especially hyperspectral imaging has gradually become a hot research topic in the scientific analysis of painting relics, due to its characteristics such as non-invasive, non-contact, fast imaging and high spectral resolution. It is mainly used to extract the intrinsic information that is difficult to observe in painting with naked eyes. In this study, two seemingly identical sketch paintings served as samples, one was painted with a 2B pencil, the other with a 4B pencil. A ground-based hyperspectral imager was used to obtain the hyperspectral data cube for the two sketch paintings in the range of 390 nm–1025 nm. And the two paintings were analyzed and compared in terms of spectral characteristics. Results indicated that hyperspectral imaging greatly facilitates the acquisition of the diagnostic spectral characteristics of different materials in painting. And the specific target in paintings can be effectively identified through hyperspectral analysis, which is of great help to painting identification. At the same time, DC characteristics and detail characteristics of the painting can be extracted, which are helpful for the researchers to analyze the painting style. In brief, it is further proved that the hyperspectral imaging has significant scientific and practical value in the protection and preservation of painting relics. © 2020 Elsevier GmbH