To enhance the antioxidant activity of third grade ripe Pu’er tea, this paper adopts different high-voltage pulsed electric fields (HPEF) to extract the tea polysaccharides and determine their antioxidant activity in each tea sample. The antioxidant activity was measured by four indices, namely the hydroxyl radical (·OH) scavenging effect, the superoxide anion (O2·–) scavenging effect, the DPPH radical scavenging effect, and the total reducibility. Based on the stepwise regression on Matlab, the mathematical model was established to depict the relationship between antioxidant activity, HPEF voltage, and HPEF frequency, and 3D relationship diagrams of the model were drawn to find the best HPEF parameters. It is concluded that the proper HPEF conditions can promote the extraction rate and antioxidant activity of tea polysaccharides in ripe Pu’er tea. The research findings open up a new way to enhance the antioxidant activity of Pu’er tea polysaccharides and shed new light on the extraction and development of natural antioxidants in Pu’er tea.