In this paper, we present the design, numerical simulations and analysis of a metamaterial absorber with two broad and flat absorption bands, including a cavity resonance band and an electrical resonance band. The electrical resonance band reveals a blue-shift with the width of cavity (d) or spacer thickness (H) increasing, while the cavity resonance band exhibits a red-shift with d or H increasing. Furthermore, electrical and cavity resonance bands can be coupled together at the same resonance wavelength to realize a single absorption band through optimizing the structure design. Finally, the effects of the variation of angles of incidence on electrical and cavity resonance bands were simulated. This method of utilizing different resonant modes for absorption bands at different wavelengths offers a simple approach to modulate dual absorption bands to single absorption band.