Ammonia selective catalytic reduction (NH3-SCR) technology is an essential method for reducing NOx emissions from flue gases, but catalyst deactivation due to poisoning remains a significant challenge, leading to reduced lifespans and increased hazardous waste. To address this issue, we propose a novel relayed regeneration strategy combining “liquid” and “gas” phase treatments to restore V2O5-WO3/TiO2 (VWTi) catalysts copoisoned by alkaline and heavy metals. The “liquid” phase employs formic acid, chosen for its acid ionization constant similar to that of vanadic acid, to remove soluble alkaline metals while preserving active vanadium oxide (VOx). The subsequent “gas” phase uses NO-mediated SO2 as a regenerant to neutralize insoluble heavy metals, restore acidity, and promote the formation of highly active polymeric VOx species, as revealed by in situ Raman spectroscopy. These processes work together to eliminate alkaline poisons, mask heavy metals, and reconstruct active catalytic sites, generating new high-activity components. This regeneration strategy fully restores the performance of copoisoned VWTi catalysts and even surpasses the activity of fresh catalysts. This study presents a sustainable and effective pathway for extending catalyst lifespans, reducing hazardous waste, and advancing the NH3-SCR technology.