The hydraulic manipulator is made use of Pasca’s law.According to Pascal’s law, if a fluid system has two large and small pistons, the pressure on both pistons must be the same, the pressure is equal to the applied pressure divided by the force area, then a small thrust is imposed on the small piston, and the pressure is transmitted through the fluid, and a larger thrust is generated on the large piston.The hydraulic mechanical arm controls the sliding of the No. 2 syringe by pushing and pulling the No. 1 syringe, and then controls the opening and closing of the gripper through a set of mechanical structures.