The invention discloses an oil well cement slurry high-temperature suspension stabilizer prepared from oil-based shale drilling cuttings. The stabilizer is prepared with a method comprising followingsteps: (1), the oil-based shale drilling cuttings are subjected to primary pyrolysis in a pyrolyzing furnace, the heating program in the air atmosphere is that the temperature is increased from room temperature to 350-400 DEG C, the heating time is 30-45 min, the heat insulation time is 75-90 min, and the oil-based shale drilling cuttings after the primary pyrolysis are ground; (2), the oil-basedshale drilling cuttings after primary pyrolysis and grinding are placed in a corundum crucible and the corundum crucible is put in a resistance furnace, and second heat treatment is performed under conditions as follows: the temperature is increased from room temperature to 800 DEG C in 45-60 min, the heat insulation time is 60-75 min, the temperature is continuously increased to 1,000 DEG C in 30-45 min, the heat insulation time is 60-90 min, then, cooling is performed in a quenching mode, and grinding is performed after drying to obtain powder with the specific surface area of 400 m<2>/Kg. The principle is reasonable, the raw materials are cheap and available, the product is high in uniformity and good in chemical stability, meanwhile, waste is changed into wealth, environmental protection is facilitated, and the stabilizer has broad industrial application prospect.