In this study, a metal nanopillar array and graphene are used to develop a metamaterial perfect absorber (MPA) with adjustable absorption efficiency, which is analyzed and optimized using a finite difference time domain method. Simulation results show that by tuning the chemical potential of graphene, an MPA with an absorption efficiency tuning range of 0.5 can be achieved, with the highest absorption efficiency of the MPA reaching 0.97. This is because incident light simultaneously excites both surface plasmon polaritons (SPP) resonance and magnetic polaritons (MP) resonance in the MPA. Analyzing the effect of the MPA's structural parameters on its absorption characteristics, the period of the nanopillars affects the resonance wavelength of SPP, and the thickness and radius of metal nanopillars affect the resonance wavelength of the MP. Therefore, the MPA's absorption wavelength can be tuned by varying nanopillar arrays' period, thickness, and radius.