Abstract: Deep eutectic solvent(DES) was a new type of green solvent, which was simple preparation, low cost, non-toxic, biodegradable, recyclable, etc, and had broad prospects in the application of lignocellulose pretreatment. In this paper, the composition, classification, preparation methods and physicochemical properties of DES were summarized. Subsequently, the research and application of DES in the field of biomass pretreatment were reviews. The mechanistic of DES pretreatment and separation of lignocellulose were concluded. The application progress of DES selectively separating lignocellulose was mainly introduced in order to provide theoretical reference for large-scale application of DES in pretreatment of lignocellulosic biomass.