The invention discloses an antenna device, an antenna switching method and a mobile terminal. The device comprises a sensing module, a switching module, a radio frequency signal source, a tuning module and an antenna body, wherein the antenna body is close to microphone end of the mobile terminal, and is connected with the radio frequency signal source through the tuning module; the sensing module is used for sensing a shielding status of the antenna body; the switching module is used for switching a tuning status of the tuning module according to the shielding status, wherein the tuning status at least comprises a first status and a second status. Therefore, the antenna performance deterioration is avoided by sending the shielding status of the antenna body at the lower part of the mobile terminal and switching the tuning status of the tuning module according to the shielding status, the performance balance of each of the left hand and right hand of the antenna is maintained, and the antenna performance when the mobile terminal is held is improved, and then the online and call experience when the user holds the mobile terminal are improved. An upper antenna can be omitted, thereby solving the problem that the head SAR testing caused by the upper antenna is hard to pass.