Background The tripartite motif (TRIM) family are important members of the Gene-finger-containing E3 ubiquitin-conjugating enzyme and are involved in the progression of hepatocellular carcinoma (HCC). Previous studies have largely focused on gene expression and molecular pathways, while the underlying role of the TRIM family in the tumor immune microenvironment (TIME) remains poorly understood. Methods We systematically explored the correlations of prominent TRIM genes with immune checkpoints and immune infiltrates in 231 HCC samples [International Cancer Genome Consortium (ICGC) cohort (n=231); The Cancer Genome Atlas (TCGA) cohort (n=370)]. A prognostic risk model was constructed using the least absolute shrinkage and selection operator (LASSO) algorithm and multivariate Cox regression analysis in the ICGC cohort. Kaplan-Meier curves based on the overall survival (OS) were used to assess differences in survival between clusters. We utilized gene set variation analysis (GSVA) to characterize the differences in biological functions. Based on univariate and multivariate Cox progression analysis, we developed a risk score signature and verified its reliability and validity. The Tumor Immune Single-cell Hub (TISCH) single-cell database was employed to evaluate the correlation of TRIM genes with the tumor microenvironment. Results Cluster 1 was preferentially associated with a favorable prognosis (P<0.001). The amino acid, fatty acid, and drug metabolism pathways were significantly enriched in cluster 2. A prognosis risk score project was established and evaluated based on the 9 independent prognostic genes (all P<0.05). The immune score and stromal scores of patients with low-risk scores were greater than those of patients with high-risk scores (all P<0.001). However, patients with a high-risk score exhibited lower responses to immune check-point inhibitors (ICIs), sorafenib, and transarterial chemoembolization (TACE) treatment (all P<0.05). Consistently, TRIM genes showed the same influence in the external TCGA cohort. TRIM gene-based signatures were implicated in TIME and their copy-number alterations dynamically impacted the abundance of tumor-infiltrating immune cells. Conclusions Our findings revealed that MID1, TRIM5, TRIM22, TRIM28, TRIM 31, TRIM37, TRIM38, TRIM47, and TRIM74 could serve as efficient prognostic biomarkers and therapeutic targets in HCC. The identified TRIM gene-based signatures could serve as important TIME mediators in HCC, potentially increasing immune treatment efficacy.