Metabolic reprogramming is a hallmark of cancer cells, enabling them to meet the heightened energetic and biosynthetic demands required for rapid growth and proliferation. Recently, non-canonical functions of metabolic enzymes have garnered significant attention in cancer research. Pyruvate kinase 2 (PKM2) has been identified as a key player in transcriptional regulation within the nucleus, presenting new opportunities for therapeutic interventions in cancer. Here, we discovered that triclabendazole, a novel benzimidazole derivative，commonly used against Fasciola hepatolithiasis, effectively inhibited the nuclear translocation of PKM2. This inhibition resulted in the downregulation of glycolytic flux, ultimately suppressing lung cancer cell proliferation. Notably, triclabendazole reduced PKM2 acetylation by promoting the interaction between PKM2 and histone deacetylase 6 (HDAC6), thus blocking PKM2 nuclear localization. Moreover, we also demonstrated that triclabendazole-mediated inhibition of cell proliferation is driven by the downregulation of glycolysis, which enhanced AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) signaling. Consistently, triclabendazole administration significantly inhibited tumor growth in vivo, correlating with the blockade of PKM2 nuclear translocation and lactate production decreased. Together, our findings revealed that triclabendazole inhibits PKM2 nuclear localization and glycolysis through an HDAC6-dependent mechanism, leading to the activation of AMPK/mTOR signaling and suppression of lung cancer cell proliferation. These results suggested that triclabendazole holds promise as a potential therapeutic agent, with the HDAC6-PKM2 axis representing a novel target for lung cancer treatment.