An antenna device and its control method is provided. The antenna device includes: a ground layer; a feeding element, connecting to the ground layer; a first radiating element, extending along a first direction and connected to the ground layer; a second radiating element, extending along a second direction which is orthogonal to the first direction, and connected the ground layer; a first switching element, coupled between the feeding element and the first radiating element, and configured to electrically connect or disconnect the feeding element and the first radiating element; and a second switching element disposed between the feeding element and the second radiating element, and configured to electrically connect or disconnect the feeding element and the second radiating element.