This application provides a multi-band shared-aperture antenna and a communication device. The multi-band shared-aperture antenna of this application includes a first antenna array, a second antenna array, and a reflection panel, where a frequency band of the first antenna array is lower than a frequency band of the second antenna array, the first antenna array includes four first dielectric plates perpendicular to the reflection panel, two adjacent first dielectric plates are perpendicular to each other, the first antenna array includes four hollowed butterfly dipole units, the dipole unit includes two radiation arms, the two radiation arms are respectively printed on two adjacent first dielectric plates, the radiation arm includes a first part and a second part, a first feeding stub is disposed on the first dielectric plate, the second part has a specified width in a direction perpendicular to the reflection panel, the second antenna array includes a plurality of second dielectric plates, four ring-shaped coils are disposed on any one of the second dielectric plates, and the ring-shaped coil is connected to a second feeding stub. An effect that a high-frequency antenna array and a low-frequency antenna array coexist is implemented without a mutual influence of standing waves.