Abstract: In this paper, a broadband dual-polarized antenna based on a butterfly-shaped vibrating arm crossed dipole is proposed. The antenna consists of a radiating oscillator, a base plate, an SMA connector, a feed sheet, a reflective cavity and a protective cover. The radiating oscillator is composed of two pairs of butterfly-shaped oscillator arms made of metallic alumina and vertically cross-fixed to the base plate, and two feeders are connected to the two SMA connectors from the underside of the base plate through the radiating oscillator for power feeding. In addition, the antenna's gain and bandwidth are improved by nesting the reflector cavity outside the oscillator, and the antenna′s environmental adaptability is improved by adding a protective cover made of PC material over the reflector cavity. The antenna is physically processed and tested, and the results show that the antenna has 46.7% -10 dB impedance bandwidth (2.90 GHz to 4.65 GHz), the isolation of the two ports is more than 32.01 dB within the operating frequency, and the antenna′s maximum gain reaches 8.35 dBi, and the cross-polarization ratio is more than 28.24 dB. The simulation and measurement results demonstrate that the designed butterfly-type arm cross dipole dual-polarized antenna has the wide bandwidth, high gain, good polarization performance, and strong directional radiation capability, which is suitable for n77 (3.3 GHz to 4.2 GHz) and n78 (3.3 GHz to 3.8 GHz) mobile communication base station systems on the 5G NR band.