A rear-end transmission device for a robotic surgical manipulator, comprising: a first rotating member connected to a first cable and a second cable, wherein the first cable and the second cable wrap around the first rotating member in opposite directions; a second rotating member connected to a third cable and a fourth cable, wherein the third cable and the fourth cable wrap around the second rotating member in opposite directions; a first pulley assembly including a first movable pulley, wherein each of the first cable and the second cable extends from the first rotating member and rides on the first movable pulley; a second pulley assembly including a second movable pulley, wherein each of the third cable and the fourth cable extends from the second rotating member and rides on the second movable pulley; and characterized by comprising: a position adjusting assembly comprising two sliders disposed in parallel and a rotating assembly disposed between the two sliders and meshing both the two sliders, wherein each of the first movable pulley and the second movable pulley is rotatably connected to a respective one of the two sliders; wherein with a rotation of the rotating assembly, the two sliders move linearly in opposite directions to concurrently adjust positions of the first movable pulley and the second movable pulley, to pull in the first cable and the second cable while releasing the third cable and the fourth cable, or to pull in the third cable and the fourth cable while releasing the first cable and the second cable. a first rotating member connected to a first cable and a second cable, wherein the first cable and the second cable wrap around the first rotating member in opposite directions; a second rotating member connected to a third cable and a fourth cable, wherein the third cable and the fourth cable wrap around the second rotating member in opposite directions; a first pulley assembly including a first movable pulley, wherein each of the first cable and the second cable extends from the first rotating member and rides on the first movable pulley; a second pulley assembly including a second movable pulley, wherein each of the third cable and the fourth cable extends from the second rotating member and rides on the second movable pulley; and characterized by comprising: a position adjusting assembly comprising two sliders disposed in parallel and a rotating assembly disposed between the two sliders and meshing both the two sliders, wherein each of the first movable pulley and the second movable pulley is rotatably connected to a respective one of the two sliders; wherein with a rotation of the rotating assembly, the two sliders move linearly in opposite directions to concurrently adjust positions of the first movable pulley and the second movable pulley, to pull in the first cable and the second cable while releasing the third cable and the fourth cable, or to pull in the third cable and the fourth cable while releasing the first cable and the second cable. a position adjusting assembly comprising two sliders disposed in parallel and a rotating assembly disposed between the two sliders and meshing both the two sliders, wherein each of the first movable pulley and the second movable pulley is rotatably connected to a respective one of the two sliders; wherein with a rotation of the rotating assembly, the two sliders move linearly in opposite directions to concurrently adjust positions of the first movable pulley and the second movable pulley, to pull in the first cable and the second cable while releasing the third cable and the fourth cable, or to pull in the third cable and the fourth cable while releasing the first cable and the second cable.