A dual-band amplitude and phase dual-regulation metasurface is proposed to achieve arbitrary beamforming shapes at two preset frequencies. By combining two resonators of different sizes in the metasurface unit, independent amplitude and phase control can be realized at the two frequency points. Under linear polarization excitation, amplitude regulation is achieved by rotating the resonators, while phase regulation is realized by changing the size of the resonator openings. An improved array synthesis algorithm, combining Taylor synthesis and genetic algorithm, is employed to obtain far-field patterns that closely match the desired shapes. The resulting phase range is relatively small, which is conducive to achieving high-efficiency array beamforming. A metasurface array that can generate a flat-top beam at 6.25 GHz and a cosecant-squared beam at 15 GHz is designed. The full-wave simulation results show that the beams generated by the designed metasurface array match the target beams very well, with low sidelobe levels. This work provides a new approach to far-field array beamforming using dual-band metasurfaces.