Ni-Mo catalyst precursors were prepared by the precipitation method. Ni-Mo bulk hydrodesulfurization catalysts were obtained from these precursors after proper drying, molding, and calcination. The effect of polyethylene glycol (PEG) with different molecular weights and in various dosages on the structure and catalytic properties of these catalysts was investigated by applying X-ray diffraction, low-temperature BET N-2 adsorption analysis, and scanning electron microscopic methods. It is shown that the structure, surface properties, and activity of the catalysts can be improved by adding PEG. The pore volume, specific surface area, and pore size of the catalysts increase gradually with increasing PEG dosage, and the dispersion of the active ingredient increases initially and then decreases.