The utility model discloses a high-temperature oil coal slurry preparation device, which comprises a coal dust storage tank, a high-temperature solvent tank, a horizontal solid-liquid mixer and a coal slurry stirring kettle, wherein the coal dust storage tank is connected with the coal dust feeding hole of the horizontal solid-liquid mixer through a coal dust conveying pipeline provided with a rotary discharge valve; the solvent outlet of the high-temperature solvent tank is connected with the liquid feeding hole of the horizontal solid-liquid mixer through a solvent conveying pipeline provided with a solvent feeding pump; the discharge port of the horizontal solid-liquid mixer is connected with the coal slurry inlet of the coal slurry stirring kettle through a coal slurry conveying pipeline; and a stirring paddle is arranged in the coal slurry stirring kettle, the discharge hole of the coal slurry stirring kettle is connected with a coal slurry circulating pump through a coal slurry discharge pipeline, the outlet pipeline of the coal slurry circulating pump is divided into two paths, one path is connected with the circulating coal slurry inlet of the coal slurry stirring kettle through a coal slurry circulating pipeline, and the other path is connected with a reaction system through a reaction material conveying pipeline. The device is easy to operate and control and can conveniently prepare uniformly mixed high-temperature coal slurry.