Based on the mechanism of achieving population inversion near the Dirac point and producing negative dynamic conductivity within the terahertz(THz) range as a result of the transient relaxation/recombination of optically excited electrons and holes,we realize the electromagnetic wave amplification at the region of THz frequency at room temperature by pumping peeling-graphene-layer structure.The expression for the dynamic conductivity of peeling-graphene-layer structure is given and relations between the dynamic conductivity and wavelength,the number of graphene layers and the optical pumping intensity are considered.We make an analysis and comparison between monolayer and multilayer structures.The gain of the structure in connection with dynamic conductivity is calculated and simulated.Results indicate that the peeling-graphene-layer structure might be used to realize the terahertz wave amplification with a high efficiency at room temperature.