It is a difficult problem to remediate acidic uranium contaminated groundwater. Nano zero valent iron (nZVI) shows a good application prospect in solving this problem, but it is prone to agglomerate, oxidize and decrease in reaction activity, which restricts its application in the remediation of the uranium contaminated groundwater. In order to solve these problems, CMC-nZVIs with different proportions (0%, 0.1%, 0.5%, 1.0%) of CMC were prepared by modifing nZVI with carboxymethyl cellulose (CMC), and their sedimentation, oxidation resistance, particle size, and uranium removal performance from acidic liquid were investigated. The results showed that with the increase of the proportion of CMC, the particle size of CMC-nZVI became smaller, the dispersion, better and the oxidation resistance, stronger. Among them, CMC-nZVI with 1.0% CMC had the smallest particle size, the best dispersion and the strongest oxidation resistance, and it had no obvious sedimentation and oxidation after 60 days. When the initial uranium concentration of acid wastewater is 5 mg / L and its initial pH, 3, CMC-nZVI with 1% CMC had the best removal performance of U(VI), with the removal rate reaching 97.64%, and the pH level being raised to 5.21. These findings provide a theoretical support for the practical application of CMC-nZVI in the remediation of acidic uranium contaminated groundwater.