In this study, we propose and investigate numerically a broadband THz metamaterial-based absorber, which is composed of superimposed Graphene Quantum Dots. Based on this idea, a new way to engineering the absorption band is introduced. We will show that using the proposed idea, it is possible to design a THz absorber with a given bandwidth. To show the capability of the idea, we consider a three-layer structure, and the top layer is superimposed graphene disks. The middle layer is a lossless dielectric thin layer and eventually gold is placed in the bottom layer. Simulation results reveal a broadband absorption in the range of (5.86THz to 7.57THz), (5.89THz to 7.56THz), and (5.89THz to 7.58THz) while absorption values respectively are above 89%, 88.49%, and 88.32%. The dielectric material is Si3N4 in the proposed structure. Also, the broadband absorption range is 7.47THz to 9.87THz with an absorption value above 80% while the dielectric material is SiO2.