Embodiments of the present invention provide an antenna apparatus, a system, and an adjusting method. The antenna apparatus is configured to be used in conjunction with an RCU (remote control unit, external remote control unit). The antenna apparatus includes a readable and writable memory and a motor. The readable and writable memory is configured to store configuration data of an antenna and antenna information corresponding to the configuration data, where the configuration data is used to control the RCU to drive the motor to move, so as to adjust an electrical down-tilt angle of the antenna.