A dual-band antenna module includes a substrate, a dual-band omnidirectional antenna, a low-frequency reflection module and a high-frequency reflection module. The dual-band omnidirectional antenna is disposed perpendicular to the substrate and is used for resonating to generate a first radio-frequency signal with a first frequency and a second radio-frequency signal with a second frequency. The low-frequency reflection module includes three low-frequency reflection units used for reflecting the first radio-frequency signal with the first frequency according to different low-frequency directional control signals. The high-frequency reflection module includes three high-frequency reflection units used for reflecting the second radio-frequency signal with the second frequency according to different high-frequency directional control signals. The low-frequency reflection units of the low-frequency reflection module and the high-frequency reflection units of the high-frequency reflection module are disposed on the substrate and are disposed around the dual-band omnidirectional antenna.