Abstract: Activated carbon is synergistically prepared from oily scum and sorghum straw. The preparation process is divided into precursor preparation with low temperature carbonization and activated carbon preparation with high temperature activation. The preparation conditions of precursor are that the mass ratio of oily scum and sorghum straw is 3:1, carbonization temperature is 450 ℃ and carbonization time is 2 h. The surface of precursor has some pores, and the heavy metal content of the leachate do not exceed the standard, which do not cause heavy metal pollution. Intensive research is carried out on the factors affecting the preparation of activated carbon with high temperature activation of the precursor by orthogonal experiment and single factor experiment. The optimal activation conditions are determined by using KOH as the activator, the mass ratio of precursor to KOH is 1:4, activation temperature is 800 ℃, heating rate is 15 ℃/min, and activation holding temperature time is 1 h. The surface of prepared activated carbon is distributed with many pores with different sizes, and several layers of small holes can be seen deeply in the large holes, pore size distribution is dominated by micropores and mesopores. All of specific surface area, pore volume, average pore diameter and iodine value surpass those of ligno-activated carbon, reaching 1648.74 m²/g, 1.84 cm³/g, 1.76 nm and 957.82 mg/g respectively.