Benzotriazole modified hydrotalcite （LDHs-BTA） was prepared using the roasting-reduction method. The corrosion resistance of LDHs-BTA to rebars was investigated using electrochemical impedance spectroscopy and chloride adsorption test. The results show that LDHs-BTA can effectively improve the corrosion resistance of rebars in simulated concrete pore solution. LDHs-BTA adsorbs Cl^- through the ion exchange between BTA^- and Cl^- in the interlayer. The adsorption follows the Langmuir adsorption model， and the maximum adsorption capacity is 308.41 mg/g. When addition of LDHs-BTA is 0.5%， the critical concentration of Cl^- for rebars corrosion increases significantly from 0.02 mol/L to 0.10 mol/L.