An automatic reversing-reposition rocker arm includes a rocker arm body, and the rocker arm body is a steel box beam. A rocker arm pivoting shaft is attached on a middle of the body. The rocker arm body has a ballast tank, a water inlet, and a water outlet. The ballast tank is located in a back end of the rocker arm body. The water inlet is located in an upper edge of the ballast tank. The water outlet is located in a lower edge of the ballast tank. A left side and a right side of a lengthwise forth end of the rocker arm pivoting shaft match each other, and a plurality of connecting devices are attached on the forth end of the rocker arm body. A plurality of gas-liquid buffers connects with the rocker arm body via the connecting devices.