Provided in the present disclosure are an antenna structure, a mobile terminal, and a method for switching antenna modes. The antenna structure of the mobile terminal comprises: an antenna unit, the antenna unit comprising an upper branch antenna, a first lower branch antenna, and a second lower branch antenna not overlapping each other in terms of deployment positions; a first sensor used for detecting whether the first lower branch antenna is shielded and outputting a first detection result; a second sensor used for detecting whether the second lower branch antenna is hielded and outputting a second detection result; a switching control circuit connected between a radiofrequency front end and the antenna unit and used for controlling, on the basis of the first detection result and of the second detection result, the on and off of connections between the radiofrequency front end and the antennas of the antenna unit.
