Abstract: Embodiments of the present invention provide a multi-sector MIMO active antenna system and a communications device, where the multi-sector MIMO active antenna system includes N columns of dual-polarized antennas, where each column of dual-polarized antennas includes one column of antenna units in a first polarization direction and one column of antenna units in a second polarization direction, antenna array elements in an antenna unit in the first polarization direction are set to have a first antenna downtilt and serve a first sector, and antenna array elements in an antenna unit in the second polarization direction are set to have a second antenna downtilt and serve a second sector.