The present disclosure provides an antenna system and a mobile terminal. The antenna system comprises a metal frame, a main board received in the metal frame, and a first feeding point, a second feeding point, a first grounding point, a second grounding point, a third feeding point, a fourth feeding point, a third grounding point, a fourth grounding point, a first tuning switch, a second tuning switch, a first matching network, a variable capacitor, a third tuning switch, a fourth tuning switch, and a second matching network disposed at the main board. The metal frame is partitioned into a first radiating portion and a second radiating portion at the bottom and a third radiating portion and a fourth radiating portion at the top.