An oil-based drilling fluid plugging agent is prepared from, by weight, 45.0-60.0 parts of a rigid plugging material, 10.0-25.0 parts of a composite fiber material, 10.0-20.0 parts of an oil-absorbing expansion material, 10.0-20.0 parts of an oil-soluble plugging material, 2.5-8.0 parts of a water-absorbing expansion material, and 0.5-2.5 parts of a surfactant. The oil-based drilling fluid plugging agent has good compatibility with an oil-based drilling fluid, and can adapt to stratum with the temperature of 60-150DEG C; and the dosage is 1-5%, the plugging agent has a good plugging effect when used to plug 10-20 mesh quartz sand beds or 0.5mm micro-crack stratums, and the pressure bearing capability of the plugging agent is greater than 6.0MPa.