In this paper, 15-bromo-1-pentadecanol, dimethylamine water, epichlorohydrin, and sodium 3-chloro-2hydroxypropanesulfonate were used as the raw materials, and the intermediates were obtained by quaternization, and then the final product, betaine surfactant TAC, was obtained by ring-opening reaction.The structure of TAC was characterized by FTIR and 1H NMR, and its performance was tested by a surface tension meter and conductivity meter. The effect of betaine surfactant (TAC) on the temperature resistance and shear resistance of thickening acid (SY) was investigated by six-speed rotational viscometer, rheometer, and swept surface electron microscope. The results showed that TAC had a low critical micelle concentration (CMC), and the lowest CMC was 0.11 mmol/L at 298.15 K. The addition of TAC with a mass fraction of 0.4% significantly improved the temperature and shear resistance of the thickening acid SY. The final viscosity of the solution was 80.54 mPa-s when the solution was heated up to 180 ℃, and the final viscosity of the solution after continuing to shear for 1 h was 75.48 mPa-s. The apparent viscosity increased by 77.52% compared with that of SY thickening acid without TAC. This system can be used for deep-well, high-temperature acid fracturing.