A modular -cyclodextrin copolymer for clay stabilization was prepared from 2-O-(allyloxy-2-hydroxyl-propyl)--cyclodextrin (XBH), acrylamide (AM), 2-acrylamido-2-methyl propane sulfonic acid (AMPS), and sodium acrylate (NaAA) via redox free-radical copolymerization. The effects of reactive conditions (such as initiator concentration, monomer ratio, reaction temperature, and pH) on the apparent viscosity of the copolymer were investigated and the optimal conditions for the copolymerization were established. The copolymer obtained was characterized by infrared spectroscopy, scanning electron microscope, viscosity measurements, rheological measurement, core stress test, and X-ray diffractometry. The crystalline interspace of MMT could be reduced from 18.95323 angstrom to 15.21484 angstrom by copolymer AM/NaAA/AMPS/XBH. And this water-soluble copolymer also showed remarkable anti-shear ability, temperature resistance, and salt tolerance (1000 s1, viscosity retention rate: 35%; 120 degrees C, viscosity retention rate: 75%; 10,000 mg/L NaCl, viscosity retention rate: 50.2%; 2000 mg/L CaCl2, viscosity retention rate: 48.5%; 2000 mg/L MgCl2, viscosity retention rate: 42.9%). (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013