Embodiments of the present invention provide an antenna port switching device and an active antenna unit (AAU). The antenna port switching device of the present invention comprises: a first printed circuit board, a second printed circuit board, and a switching module. The first printed circuit board comprises external antenna port groups and internal antenna port groups. The external antenna portgroups comprise a first external antenna port group and a second external antenna port group. The internal antenna port groups comprise a first internal antenna port group and a second internal antenna port group. The second printed circuit board comprises a metal microstrip, and is used for communicating the first external antenna port group and the second external antenna port group with corresponding internal antenna port groups, respectively. The switching module is used for adjusting opposite positions of the first printed circuit board and the second printed circuit board according to the configuration mode of a radio frequency module. The embodiments of the present invention implement an antenna applicable to multiple AAU configurations.