The present invention discloses a narrow band slot antenna with a coupling suppression. The slot antenna includes a medium plate (1), a copper-clad layer (2), an A-capacitor (3), and a B-capacitor (4). The copper-clad layer (2) has an A-slot (21) and a B-slot (22) thereon, the A-capacitor (3) and the B-capacitor (4) are respectively mounted inside and at two ends of the B-slot (22). The present invention loads the capacitors at a specific position on a finite medium plate to increase the isolation between the antennas, which is beneficial to rectify the slot antenna.