Superplasticizers are key components to enhance greatly the workability of concrete. A new carboxylic acid-based copolymer was synthesized and evaluated as a superplasticizer. This copolymer was prepared from methacrylic acid and 2-acrylamido-2-methylpropane sulfonic acid through free radical polymerization. The test results on cement pastes indicate that this copolymer could uniformly disperse the cement particles and improve the fluidity of the system. Compared to the commercially available naphthalene-based superplasticizer, the polymer requires less amount to achieve the same minislump value, and provides longer slump retention time. Thus the synthesized resin has a potential to become a superplasticizer. Finally, the workability and compressive strength of concrete with this new admixture were also tested, and compared with that of the commercial superplasticizers.