Objective To investigate the expression of programmed death 1 (PD-1) / programmed death ligand 1 (PD-L1) in peripheral blood of patients with primary hepatocellular carcinoma (HCC) pre and post-transcatheter arterial chemoembolization (TACE) and its clinical significance. Methods A total of 20 healthy volunteers and 28 HCC patients were enrolled. The levels of PD-1 and PD-L1 on the surface of CD4 + T cells, CD8 + T cells and antigen- presenting cells (APC) in peripheral blood were detected by flow cytometry. Relationship between the expression of PD-1 and PD-L1 and the differentiation and outcomes of tumor was analyzed. Results The levels of PD-1 and PD-L1 on the surface of CD4 + T cells, CD8 + T cells and APC in peripheral blood of HCC patients were increased than those in healthy volunteers (P < 0.05). The expression of PD-L1 on the surface of CD4 + T cells, CD8 + T cells and APC in peripheral blood of HCC patients was decreased after TACE comparing to those in patients prior to treatments, while no obvious difference was identified in patients prior to and post treatments. High expression of PD-1 and PD-L1 was determined in patients with poor differentiation or poor outcomes. Conclusions The levels of PD-1 and PD-L1 in peripheral blood of patients with hepatocellular carcinoma are responsive to TACE and clinical prognosis.