Abstract: Activated carbon fiber (ACF) was modified with different concentration and temperature of acid and alkali solutions. It was concluded that the ACF modified with 8 mol/L, 90 ℃ mixed acid had best removal effects for DBT. The structure of modified ACF was characterized with BET, FTIR and Boehm titration. The results showed that the specific surface area, pore volume and oxygen-containing functional groups of ACF were significantly increased after modification. The absorption capacity of the modified ACF reached 49.61 mg/g under the optimized conditions of ultrasonic time 80 min, adsorption temperature 50 ℃, adsorption time 1.5 h, and mass ratio of oil to adsorbent of 100:1. The modified ACF had good reproducibility to remove DBT, and the fitting of isothermal adsorption data was in accordance with Langmuir equation, the saturated sulfur capacity could reach 57.80 mg/g.