Cellulose, as the most abundant natural biopolymers in the world, has attracted much attention in recent years, as concerns have been raised on environmental issues associated with the use of petroleum related products. Nano crystalline cellulose (NCC) is a special type of cellulose that is derived from renewable and sustainable resources such as cotton and wood. NCC has a large specific surface area with plentiful hydroxyl and anionic sulfate ester groups, which make NCC a perfect substrate for preparing composite absorbing and/catalytic materials for wastewater treatment. This paper reviews recent research on the applications of NCC in wastewater treatment.