An amphoteric polyacrylamide thickener was synthesized using 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylamide (AM), and dimethyl diallyl ammonium chloride (DMDAAC). According to the experimental results, the best polymerization conditions were as follows: temperature of 45 ℃, AMPS:AM:DMDAAC mass ratio of 1:3:1, and monomer, initiator, guide agent, crosslinking agent, and urea concentrations of 27%, 0.6%, 0.15%, 0.3%, and 1%, respectively. The apparent viscosity, measured at room temperature with a six-speed rotational viscometer, was 135 and 45 mPa·s in the absence and presence of 20% HCl, respectively. The temperature resistance of the thickener solution was evaluated using an AR2000ex rheometer; at 120 °C and a shear rate of 170 s–1, its apparent viscosity was 99.7 mPa·s. Moreover, the chemical composition and morphology of the synthesized thickener were investigated via Fourier-transform infrared spectroscopy and scanning electron microscopy, respectively.