In this study, MnO2 nanotubes, nanowires, and nanoparticles were synthetized by a hydrothermal method, after which the NO removal process with sodium persulfate solution catalyzed by MnO2 of different shapes was studied and compared. It could be verified that MnO2 nanowires showed the best NO removal efficiency of 91.2% with the catalyst concentration of 0.06 mol/L. As illustrated from the XRD, SEM, TEM, and XPS analysis results, the relatively higher activity of MnO2 nanowires could be attributed to its low crystallinity and the presence of more lattice oxygen. The reaction mechanism was further confirmed by using the electron paramagnetic resonance technique, which verified the promotional effect by capturing the signal of hydroxyl (center dot OH) and sulfate (SO4-center dot) radicals. Additionally, free radical-quenching experiments also verified the decisive impacts of these two radicals on the removal system, where sulfate (SO4-center dot) radicals played a major role.