The abnormal accumulation of alpha-synuclein (alpha-syn) is a crucial factor for the onset and pathogenesis of Parkinson's disease (PD), and the autophagy-lysosome pathway (ALP) contributes to alpha-syn turnover. AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR) regulate autophagy by initiating the macroautophagy cascade and promoting lysosomal biogenesis via increased transcription factor EB (TFEB) activity. Hence, activation of AMPK-mTOR-TFEB axis-mediated autophagy might promote alpha-syn clearance in PD. Harmol is a beta-carboline alkaloid that has been extensively studied in a variety of diseases but rarely in PD models. In this study, we aimed to evaluate the effect and underlying mechanism of harmol in PD models in vitro and in vivo. We show that harmol reduces alpha-syn via ALP in a dose- and time-dependent manner in cell model that overexpressed human A53T mutant alpha-syn. We also demonstrate that harmol promotes the translocation of TFEB into the nucleus and accompanies the restoration of autophagic flux and lysosomal biogenesis. Importantly, harmol improves motor impairment and down-regulates alpha-syn levels in the substantia nigra and prefrontal cortex in the alpha-syn transgenic mice model. Further studies revealed that harmol might activate ALP through AMPK-mTOR-TFEB to promote alpha-syn clearance. These in vitro and in vivo improvements demonstrate that harmol activates the AMPK-mTOR-TFEB mediated ALP pathway, resulting in reduced alpha-syn, and suggesting the potential benefit of harmol in the treatment of PD.