In this paper, by characterizing two samples, nanoporous gold (NPG) and graphene-coated nanoporous gold (G@NPG), using scattering near-field scanning optical microscopy (s-SNOM), it is found that graphene can weaken the localized surface plasmon resonance (LSPR) intensity of NPG. In order to investigate the reason why graphene weakens the hotspot of NPG, this paper analyzes the phenomenon by using finite-difference time-domain simulation, and the simulation results are consistent with the characterization results of s-SNOM. From the absorption spectra of the two samples, we find that graphene can eliminate the phenomenon of multiple LSPR modes caused by the irregular structure of NPG. The simulation results of graphene-coated gold nanoparticles (G@NP) show that the peak position of the LSPR peak of graphene-coated NPs shows an obvious red shift and the peak width increases, indicating that the lifetime of the plasmon is attenuated. This explains why the near-field signal intensity of G@NPG is weaker than that of NPG, and why graphene can eliminate the multiple LSPR modes of NPG. In the design of wavelength-selective NPG devices, graphene can be used as an alternative material to modulate the LSPR of nanoporous gold.