The invention provides a self-catapulting launching device for a guided missile. The self-catapulting launching device comprises a flow-guiding cone, a limiting mechanism, a buffering device, a long guide rail, a short guide rail and adaptors; the flow-guiding cone is fixedly connected to the bottom end of a launching cylinder, the buffering device is fixedly connected to the outlet of the launching cylinder, the long guide rail and the short guide rail are fixed to the inner wall of the launching cylinder in the axis direction of the launching cylinder and are staggered and evenly distributed in the launching cylinder, grooves of the adaptors are slidingly matched with the long guide rail, gaps between two adjacent adaptors are slidingly matched with the short guide rail, the limiting mechanism is fixedly connected to the inner wall of the launching cylinder, the adaptors are limited to move to the interior of the cylinder in the axis direction of the launching cylinder, and after guided missile is filled, a closed space is defined by the bottoms of the adaptors, the bottom of the guided missile, the end face of the bottom of the long guide rail and the end face of the bottom of the short guide rail in the launching cylinder. The initial launching precision of the guided missile can be improved, and the manufacturing cost and the maintenance cost of the launching device are effectively lowered.