In recent years, long-chain amidosulfobetaine surfactants are interesting additives in the acidification process. However, there is a strong interaction between them and Fe(III) ions, which has a negative effect on viscoelastic behavior. In this work, the rheological behavior of a spent solution of amidosulfobetaine and iron ions as an impurity in the acidification process was investigated. The results showed that by increasing the iron ion concentration, the viscosity of the solution increased slightly, followed by a significant decrease and subsequent precipitation of the viscoelastic surfactant. By increasing the temperature, the iron tolerance decreases noticeably.