Hydroxyl-iron polycations-intercalated montmorillonite(Fe-Mt) was successfully synthesized and characterized using the methods of XRD, FTIR, TEM, and N₂_adsorption/desorption analysis. The adsorption of the target contaminant tetracycline hydrochloride(TC) on Fe-Mt from aqueous solutions was examined in batch experiments. Effects of the pH values of solution and types and concentrations of anions were systematically investigated. The adsorption isotherms of Fe-Mt at pH=3.0 can be fitted well with both the Langmuir and Freundlich models, with the former(R²>0.98) better than the latter(R₂<0.98), which indicated that the monolayer adsorption was the dominant model for the TC adsorption. In contrast to the starting montmorillonite(Mt), the adsorption capacities of Fe-Mt were increased with the increasing concentration of anions under the acidic solution condition that was favorable for the TC adsorption. Under a certain optimum condition, the types of anions can dramatically influence the TC adsorption on Fe-Mt, and exert the effect on the adsorption capacity in order of SO₄^2->>NO₃^->Cl^-, corresponding to the theoretical maximums of 500.0, 339.0 and 316.5 mg/g, respectively. At the acidic pH, the TC adsorption on Fe-Mt displays the coexisting of multi-models and the surface complexation, with the anion electrostatic attraction being the dominant model.