The heterologous expression of the tannase gene afTanA in Pichia pastoris and the recombinant enzyme were analyzed. The effects of recombinant tannase on the antioxidant activity of persimmon juice were also discussed. It was found that the afTanA gene consisted of 1 767 bp base， encoding 588 amino acids and one stop codon， and there was one Kex 2 restriction site （Lys315-Arg316）， and the catalytic sites were Ser202， Asp455 and His501. The recombinant strain was induced by 48 h， and the activity of AfTanA was 678 U/mL. The optimum reaction temperature for AfTanA is 40 °C and the optimum pH is 5.0. Zn2+ increased the activity of AfTanA by 49.65% under low concentration （1 mmol/L）， while Cu2+ and Fe3+ decreased the activity of the enzyme by about 78% and 98%， respectively. At high concentration （5 mmol/L）， Zn2+ reduced the activity of AfTanA by 47.12%， The activity of AfTanA was inhibited completely by Cu2+ and Fe3+. The antioxidant ability of persimmon juice increased significantly， and after treated with recombinant tannase AfTanA the DPPH， ABTS free radical and ·OH scavenging rate increased by 15.79%， 12.78% and 3.4%， respectively. In summary， tannase AfTanA has been highly expressed in Pichia pastoris and has good application potential in the juice processing industry.