The invention discloses a reinforced transition earthing device comprising insulating sheaths arranged on three phase of a three-phase bus. Mounting gaps are arranged on the insulating sheaths; and parts of bus are exposed in the mounting gaps. An earthing device is arranged on the mounting gap detachably and can be clamped in the mounting gap. A clamp plate that can clamp the bus and is provided with metal contact points is arranged at the earthing device; and the metal contact points are connected with an earth wire. According to the invention, the mounting gaps cooperating with the earthing device are especially arranged on the bus and punching is not needed, so that the bus can be protected effectively. With the mounting gaps, situations of lingering and playing of small wild animals are taken into consideration, so that an inter-phase accident caused by wild animals can be prevented. After operation completion, the mounting gaps and the surrounding parts can be sealed by a sealing device, thereby protecting usage safety of the bus contact points.