Superoxide dismutase （SOD） is a kind of main antioxidant enzyme produced in organism， which can eliminate superoxide anion produced by respiratory metabolism. Milk contains SOD， and SOD is added to dairy products as a food additive to improve the oxidation resistance of products. In order to study the antioxidant activity of milk tablet enriched with SOD（MKTES） and its function from the perspective of its effect on the electrical potential difference（EPD） of 12 acupuncture meridians， the oxidation-reduction potential （ORP）， DPPH free radical scavenging capacity and SOD activity were studied respectively for the milk tablet （1.00 g milk powder） and MKTES （0.99 g milk powder + 0.01 g 2.53×106 U/g SOD）. 20 healthy volunteers were recruited and randomly divided into two groups for a double-blind clinical trial. The subjects in milk tablet group took sublingually 1 milk tablet， while the MKTES group took 1 tablet of MKTES. The EPD of 12 meridians on the left side were recorded in real time. Samples were took at the 25th min. The whole procedure continued 85 mins. The results showed that SOD activity and reducibility（ORP value decreased） of MKTES were significantly increased compared with the milk tablet. DPPH radical scavenging rate increased at the concentration of 1.250 and 1.562 mg/mL but decreased at 3.125 mg/mL. The results of EPD monitoring showed that the milk tablet had no effect on the EPD of Lung Meridian and Gallbladder Meridian， while MKTES had. Compared with the milk tablet， MKTES has a stronger effect on the EPD of Large Intestine Meridian， Spleen Meridian， Small Intestine Meridian， Bladder Meridian， Triple Energizer Meridian and Liver Meridian. Both milk tablet and MKTES have certain effects on the EPD of Stomach Meridian， Heart Meridian， Kidney Meridian and Pericardium Meridian.