〔Abstract〕 Objective To investigate the expression of urocanase domain containing 1(UROC1) in Hepatocellular carcinoma(HCC) and its effect on the development of HCC. Methods UROC1 expression and prognostic data in tumor and para-tumor tissues from protein mass spectrometry and TCGA database were analyzed. Immunohistochemical staining, real time quantitative polymerase chain reaction(qPCR) and Western blot experiments were utilized to verify the expression of UROC1 in HCC. The effect of UROC1 expression level on tumor differentiation was analyzed by HE staining to determine the tumor differentiation level. Hep3B and LM3 cell lines stably overexpressing UROC1 and its mutants were constructed for in vitro phenotyping experiments. Effects of UROC1 on HCC cell proliferation and migration were explored by cell counting kit-8(CCK-8) assay, colony formation, EdU assay, scratch assay and Transwell assay. Results The results of database analysis showed that UROC1 was generally downregulated in HCC tissues,and patients in the UROC1 low-expression group had a worse prognosis. Immunohistochemical staining and scoring,qPCR and Western blot experiments verified the low expression of UROC1 in HCC. Immunohistochemical staining of tumor tissues with different differentiation levels demonstrated that the poorer the differentiation of HCC tissues,the lower the expression level of UROC1. CCK-8,colony formation and EdU assays suggested that overexpression of UROC1 inhibited the proliferation of HCC cells. The results of scratch and Transwell assays showed that overexpression of UROC1 inhibited the migration of HCC cells. However,the results of the above experimental phenotypes after active site mutation converged with those of the control group. Conclusion UROC1 is lowly expressed in HCC tissues,and overexpression of UROC1 in HCC cells may inhibit the ability of cell proliferation and migration.