Abstract: Silicosis, one of the most serious occupational diseases in the world, is a complex pathological process with multi-cell involvement and multi-factor regulation, and its pathogenesis has not been fully elucidated.Protein phosphatase 2A (PP2A) regulates tumor signaling pathways, cell development and cell cycle.The regulatory subunit B of PP2A binds to the core enzyme, resulting in tissue expression specificity and substrate specificity of the PP2A holoenzyme complex.Protein phosphatase 2A regulatory subunit B"α (PPP2R3A) is a subunit of PP2A regulatory subunit B", which is a regulator of cell proliferation.However, the role of PPP2R3A in pulmonary fibrosis is still unclear.In this study, the pulmonary fibrosis model was established by endotracheal infusion of silica (SiO₂, 250 mg/kg).Human pulmonary fibroblast-adult cells (HFP-a) were stimulated with 5 ng/mL TGF-β1 to construct fibro-related cell models.The transcription level of Ppp2r3a was detected by qRT-PCR assay.Immunofluorescence and Western blot experiments were performed to detect protein levels.Cell viability was detected by CCK-8 assay.The cell migration ability was detected by scratch test.Experimental results showed that silica nodules and collagen deposition were obvious in the SiO₂ group, and the expression of PPP2R3A in lung fibroblasts increased, which could affect cell viability and migration ability, and may promote the progression of pulmonary fibrosis by regulating the expression of p53 signaling pathways.This study provides a new idea for the prevention and treatment of pulmonary fibrosis.