The worm gear type rotary drive has the characteristics of reverse self-locking, which can realize reverse self-locking, that is, the worm wheel can only be driven by the worm wheel, and the worm wheel cannot be driven by the worm wheel. This feature enables the slewing drive to be widely used in truck cranes and access platforms. The structure of the innovate slew drive also greatly improves the operation stability and safety factor of the main engine.