Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterized by irreversible lung scarring with a poor prognosis. Emerging evidence has revealed that IPF is an aging-related disease, and the development of cellular senescence plays a pivotal role in persistent remodeling and fibrotic scarring, acting as a key mechanism in the pathophysiology of IPF. Exploring therapeutic strategies for modulating cellular senescence can provide crucial insights into unraveling IPF processes. Here, we have identified Nitazoxanide (NTZ), an FDA-approved antiprotozoal agent, has specific effects on inhibiting cellular senescence development. In the bleomycin and D-galactose-induced senescence model, NTZ effectively inhibits senescence associated-β-gal staining and preserves cell proliferation ability. We also found that NTZ effectively impedes senescence progression in the bleomycin-induced pulmonary fibrosis model, while mitigating the release of senescence-associated secretory phenotype and alleviating pulmonary fibrosis. The anti-senescence effect of NTZ is mechanistically dependent on the preservation of nuclear SIRT1 expression. We observed that PI3K induces a WIPI1-mediated nucleophagic degradation of SIRT1, while NTZ effectively inhibits PI3K and suppresses WIPI1 expression, thereby maintaining SIRT1 expression in the nucleus and exerting its anti-senescence function. Collectively, our research has shown that NTZ can inhibit PI3K in senescence progression, leading to the inhibition of WIPI1-mediated SIRT1 nucleophagic degradation. As a result, NTZ alleviates fibrosis by inhibiting senescence development.