The invention discloses a torque transmission device. The torque transmission device comprises a first shaft assembly, a second shaft assembly and a piston assembly, wherein the first shaft assembly and the second shaft assembly are separately provided with combined surfaces which face towards each other; a circular-arc plunger piston is formed on the combined surface of the first shaft assembly;a bump is formed on the combined surface of the second shaft assembly; a circular-arc cavity is formed in the bump; the circular-arc plunger piston is sleeved by the circular-arc cavity, and is in sliding fit with the circular-arc cavity in a sealing mode; an oil cavity is further formed on the second shaft assembly, and is arranged in the axial direction; one end of the oil cavity penetrates through the end surface of the second shaft assembly and the other end of the oil cavity penetrates into the circular-arc cavity; the piston assembly is arranged in the oil cavity in a sealing mode; and hydraulic oil is contained in the oil cavity and the circular-arc cavity. The oil cavity communicates with the circular-arc cavity to form a through cavity which is filled with hydraulic oil; and whentorque suddenly changes, the circular-arc plunger piston moves in the circular-arc cavity to apply pressure to the hydraulic oil, and counter-acting force, on the circular-arc plunger piston, of hydraulic oil is gradually increased, so that rigid impact generated when a conventional universal shaft is connected is avoided, and the buffer effect is achieved.