FeS nanoparticles with uniform size have been prepared through a facile route using (sodium carboxymethyl cellulose) CMC as soft template. The nanoparticles are about 4-6 nm by observation of transmission electron microscopy (TEM). The CMC template could also stabilize the FeS nanoparticles and resist aggregation. It is important to note that the size of nanoparticles can be easily controlled by the concentration of iron and sulfur source during the synthetic process. Interestingly, the FeS nanoparticles could assemble into rod-like morphology at higher concentration. More importantly, the CMC-stabilized FeS nanoparticles exibit enhanced performance for Cr(Ⅵ) removal as compared with FeS synthesized without CMC stabilizer.