As a new temporary consolidation and extraction material in archaeological excavation, menthol has been used successfully in the No.1 pit at Emperor Qinshihuang’s Mausoleum Site Museum. However, it is necessary to investigate related safety issues. In this paper, the safety issues related to applying menthol to relics from the No.1 pit of Emperor Qinshihuang’s Mausoleum Site were assessed. The site soil and polychrome lacquer were analyzed. The pore configuration of the site soil, the polychrome lacquer surface morphology and the cracks in the polychrome lacquer before and after treatment with menthol were compared. Whisker growth on the substrate during menthol sublimation was observed and discussed whether it is hazard to fragile remains. A GCMS method was used to analyze the residue left from methanol treatment. The recrystallization on the relics is discussed during the evaporation of menthol. Overall this study showed that the physical structures of site soil and polychrome lacquer were unchanged. So it is safe to use menthol on unearthed polychrome relics in the Qinshihuang’s Terracotta Army site.