Objective To analyze the expression of pituitary tumor transforming gene 1 (PTTG1) in hepatocellular carcinoma (HCC) and its clinical prognostic implication. Methods Firstly, the Tumorsurvival and HCCDB databases were used to analyze the expression of PTTG1 gene and its co-expressed genes in HCC tissues. Secondly, cBioPortal, MetaScape, Kaplan-Meier Plotter databases were used to analyze the mutations, GO functions and KEGG of the co-expressed genes of PTTG1 in HCC, and to analyze the effects of co-expressed genes on the overall survival (OS) and prognosis of HCC patients. Finally, the TIMER database was used to analyze the expression of PTTG1 gene in the HCC immune microenvironment and its relationship with immune cells, and the impact of various immune cells on OS and prognosis of HCC patients. Results PTTG1 gene was highly expressed in HCC tissues and was not conducive to OS of HCC patients. PTTG1 had 19 significant co-expressed genes in HCC, and its co-expressed genes were also highly expressed in HCC, which was also not conducive to OS of HCC patients. The GO function of PTTG1 gene and its co-expressed genes was mainly enriched in cell division, mitosis and protein kinase binding, while KEGG was enriched in cell cycle, p53 signaling pathway and human T-lymphotropic virus (HTLV) infection. PTTG1 and its co-expressed genes were mutated to some extent in HCC, and significantly shortened OS and DFS in HCC patients. PTTG1 gene was positively correlated with the expression of various immune cells in the immune microenvironment of HCC, but the expression of various immune cells was also not conducive to OS of HCC patients. Conclusion High expression of PTTG1 is not conducive to survival and prognosis of HCC patients.