With the rapid development in new energy industry, the research of high-performance lithium-ion battery has become a hot spot nowadays. As one of the most important components of lithium-ion batteries, separator not only determines the internal structure and internal resistance of lithium-ion batteries, but also plays a crucial role in the capacity, cycling and safety performance of the batteries. Cellulosic materials are abundantly sourced and environmentally friendly, and separators prepared from cellulose-based materials have high porosities, large surface-to-volume ratio, and high ionic conductivity, promising to be an excellent candidate for replacing conventional polyolefin separators. Different types of cellulose used in lithium-ion battery separators are outlined, with a comprehensive discussion and summary provided on the preparation techniques of cellulose separators and their performance. Finally, the problems to be solved in the field of cellulose lithium-ion battery separators and the development prospects of cellulose in the separator field are presented.