Abstract: Aiming at the dual-frequency operation of 5G smart antennas, a reconfigurable antenna based on active frequency selective surface is proposed. The antenna consists of a frequency reconfigurable feed antenna in the shape of a bow-tie and a cylindrical active frequency selective surface (AFSS). The feed antenna adopts a coplanar waveguide feed of bow-tie shaped monopole. The active frequency selection surface consists of a periodic structure with a symmetrical hook-shaped slot, which is loaded by a PIN diode, enabling AFSS to be in reflection mode and transmission mode in the two 5G frequency bands 3.4−3.6 GHz and 4.8−5.0 GHz. By using this AFSS, the electromagnetic waves excited by the feed antenna can be spatially controlled, and the omnidirectional and directional beam switching of the two frequency bands can be realized, and the horizontal plane beam scanning can also be realized. Processed and tested according to the simulated antenna model, the test results show that the working frequency band of the antenna covers the above two frequency bands, a low-frequency directional beam gain of 7.6 dBi, and a high-frequency directional beam gain of 8.6 dBi; and can achieve high/low frequency dual-band switching, omnidirectional/directional beam switching and beam scanning within 360° in the horizontal plane. This antenna has the characteristics of flexible beam switching, simple structure, easy processing, low power consumption, low cost, and it has certain application value in 5G new generation wireless communication system.