[Abstract] Objective: To study the application value and possible mechanism of monocarboxy transporter, (MCT1) in the prediction of prognosis for the patients with hepatocellular carcinoma (HCC). Method: We selected the tissues of HCC patients after liver resection, and used RT-PCR to estimate the expression of MCT1 and divided the patients into MCT1 high and MCT1 low groups; the phenotype and activation of the immune cells from the peripheral blood as well as the immune statues of the resected liver tissues from both groups were analyzed. A retrospective analysis of the relationship between the overall survival and disease-free survival rate to the expression of lactate or MCT1 between 43 HCC patients who underwent liver surgery in the year 2018 was also compared. Results: Although there was no difference in the phenotype of immune cells from peripheral blood, CD4+ T cells were easier to transform into Treg cells under the stimulation of lactic acid in the high MCT1 expression group; under the environment of lactic acid, the Treg cells from the MCT1 high expression group presented a significant increase of metabolism level; MCT1 high expression group had lower immune cell infiltration and up-regulated expression of anti-inflammatory cytokines (Foxp3, CTLA3, IL-10). The OS and DFS rate were much worse in MCT1 high patients comparing with MCT1 low group. Conclusion: MCT1-Treg related targets may serve as a new target for the diagnosis, therapeutic and prognosis prediction of HCC.