The invention discloses an LTE-A (Long Term Evolution-Advanced) MIMO (Multiple Input Multiple Output) antenna apparatus with an all-metal housing. The antenna apparatus includes an all-metal back cover, wherein two relatively side frames are arranged on the all-metal back cover; two groove holes are respectively formed in the two side frames at intervals; a first capacitor and a second capacitor are respectively in bridge connection with the two groove holes at the same side; one end of the first capacitor is connected with one side the corresponding groove hole, and is arranged at the side frame between the two groove holes; the other end of the first capacitor is connected with a feed signal port by crossing the groove hole; one end of the second capacitor is connected with one side of the corresponding groove hole, and is arranged at the side frame between the two groove holes, and is connected with the second capacitor in another groove hole at the same side in series; and the other end of the second capacitor is connected with the side frame at the other side of the corresponding groove hole. The LTE-A MIMO antenna apparatus can realize 4*4LTE-A MIMO antennas in the limited space of the all-metal housing, and can increase the number of antennas so as to improve the channel capacity and the data transmission rate.