<p>Hepatocellular carcinoma (HCC) is one of the most prevalent malignant tumors worldwide, and its occurrence and development are intricately associated with the abnormal regulation of various genes and signaling pathways. Exosome Component 3(EXOSC3) is involved in the occurrence and growth of tumors. However, the exact mechanisms by which EXOSC3 influences HCC remain to be elucidated. Bioinformatics analysis method was used to detect the expression of EXOSC3 in HCC, qRT-PCR and Western blot were used to verify EXOSC3 expression in HCC cell lines.CCK-8 and colony formation assay was used to evaluate the effect of EXOSC3 on tumor proliferation, and validate the impact on cell migration and invasion through Transwell and Wound healing assay. Flow cytometry and Hochest staining were used to investigate the effect of EXOSC3 knockdown on the cell cycle and apoptosis of HCC. Western blot method was used to detect proteins expression. In HCC tissues, EXOSC3 mRNA and protein expression levels were notably higher than those in normal liver tissues and these levels correlated with poor prognosis. After knocking down EXOSC3, cell proliferation, colony formation, and metastasis were significantly inhibited in HCC. Flow cytometry and Western blot analyses showed that knockdown EXOSC3 promoted HCC cell apoptosis and inhibited cell cycle progression with reduced G1/S checkpoint protein expression. Furthermore, knockdown EXOSC3 activated P53 and decreased retinoblastoma protein (RB1) phosphorylation, suggesting that EXOSC3 functions via the P53 pathway in HCC. EXOSC3 has potential as a prognostic biomarker in HCC. Knockdown EXOSC3 leads to cell cycle arrest and consequently inhibits the proliferation of liver cancer cells by activating the P53 signaling pathway and concomitantly suppressing the expression of crucial regulatory proteins. These results not only establish EXOSC3 as a clinically relevant prognostic indicator but also highlight its therapeutic potential as a molecular target for HCC intervention strategies.</p>