The invention relates to an active carbon preparation method used for the field of chemical industry and an adsorption desulfurization method by refinery distillate oil. The method is characterized in that active carbon is prepared by a low-temperature one-step method, and adsorption desulfurization is carried out by the refinery distillate oil. A technical scheme is characterized by comprising the following steps: adding the washed, dried and crushed wood chips according to a certain proportion in a nitric acid aqueous solution and a composition of 3-5 nitrate aqueous solutions, performing static equivalent volume dipping on the material at the temperature of 20-30 DEG C for 12-24 h; placing the above prepared solution in a muffle furnace, charing the material under condition of N2 atmosphere and the temperature of 300-400 DEG C, activating the material, and modifying the material and keeping for 2-3 h, and cooling the material to room temperature to obtain the active carbon; finally placing the above prepared active carbon in a fixed bed, under condition of the temperature being 150-360 DEG C and the air speed being 0.5-1 h<-1>, introducing the refinery distillate oil in an active carbon bed layer of the fixed bed for high-temperature adsorption desulfurization, and at the same time, performing hole-reaming activation. The preparation method of the active carbon enables one-step completion, and has the advantages of simple process and environmental protection, the diffusion resistance during an adsorption process is small, and the desulfurization rate for the distillate oil can reach 71.55-91.67%.