The invention discloses an antenna for a full metal casing handset. The antenna comprises a first square medium substrate (9) and a second long strip medium substrate (10), wherein a right side of thesecond medium substrate (10) fits an inner side of a handset metal outer frame, a right side of the first medium substrate (9) is connected with a left side of the second medium substrate (10), a topend of the first medium substrate (9) is level with a top end of the second medium substrate (10), a lower surface of the first medium substrate (9) is fully pasted with first metal floor (0), a lower surface of the second medium substrate (10) is provided with a second metal floor forming a third-order radiation groove, an upper surface of the first medium substrate (9) is provided with a microstrip feed port (1), a first microstrip feed line (2), a first capacitor (5) and a second capacitor (6) and further comprises a second microstrip feed line (3), one end of the second microstrip feed line (3) is at the upper surface of the first medium substrate (9), and the other end of the second microstrip feed line (3) is at the upper surface of the second medium substrate (10). The handset antenna is advantaged in that the structure is simple, and profile is compact.