A kind of cellulose nanoparticle was prepared from cotton fibre as received and pre-treated with DMSO respectively. The properties were characterized by TEM，WXRD，IR，DSC，TGA and Element Analysis. The results indicated that cellulose nanoparticle has a rodlike shape, the length is about several hundred nanometer and the diameter is about dozens of nanometer. The nanoparticle has the same functional group with neat cellulose, and carbon and oxygen elements content in the nanoparticles are more close to the theoretical value than the neat cellulose. The hydrogen element content is higher than the theoretical value. The nanoparticle has the same crystal type with neat cellulose ,and the thermal stability of the nanoparticle is worse than the neat cellulose, especially in pre-treated nanoparticles.