Natural halloysite nanotubes (HNTs) were modified with a silane coupling agent, N-beta-aminoethyl-gamma-aminopropyl trimethoxysilane (KH-792), to form a new adsorbent for Cr(VI) removal. The as-prepared product was characterized by FTIR spectroscopy, TGA, TEM, and specific surface analysis. The results showed that KH-792 was successfully grafted onto the halloysite surface. Modified HNTs exhibited a rapid adsorption rate for Cr(VI) and approached 95% of the maximum adsorption capacity within 5 min. The effects of initial Cr(VI) concentration, temperature, pH, and ionic strength on the adsorption capacity were investigated in batch experiments. The results showed that low temperature was favorable to improve adsorption efficiency, and the adsorption capacity decreased significantly with the increase of pH and ionic strength. The optimum pH was found to be 3-5. The main adsorption mechanism was considered to be electrostatic interaction between protonated amino groups on the adsorbent surface and negatively charged Cr(VI). The results above confirmed that modified HNTs had the potential to be utilized as a low-cost and relatively effective adsorbent for Cr(VI) removal.