Ground anchor device and using method

The invention relates to the technical field of buildings, in particular to a ground anchor device and a using method. A ground anchor device is suitable for being fixed to a drill hole and comprises an anchoring cylinder, a ground anchor rod and a ground anchor rod, the expansion structure is arranged in the containing space, and the expansion structure comprises an air bag and an air inlet pipe connected with the air bag in a penetrating mode; the anchoring structure comprises a lateral anchoring nail, and the lateral anchoring nail partially extends into the inner side wall of the containing space; in the installation process, air is inflated into the air bag through the air inlet pipe so that the air bag can be rapidly expanded, and after the air bag makes contact with the lateral anchoring nail, the air bag applies pressure, facing the inner wall of the drill hole, to the lateral anchoring nail to drive the lateral anchoring nail to move towards the inner wall of the drill hole till the preset depth is r