Abstract: Experiments were conducted to determine the effect of tea polyphenols ( TP) on the lactation performance, blood biochemical parameters and antioxidant capacity of lactating rats under different dietary conditions. 40 pregnant SD rats were randomly divided into four groups with 10 repeats in each group and 1 in each repeat. Four kinds of diets were designed by 2×2 Latin square experiment:high-energy diet group (HE) , low-energy diet group (LE) , high-energy diet+500mg/kg tea polyphenols group (HE-TP) , low-energy diet+500mg/kg tea polyphenols group (LE-TP) . The whole trial period was 40 days. The results showed that:Adding TP significantly increased the lactation yield of postpartum rats and the level of PRL, E2 in mammary gland (p<0.05) , there's no significant effect on feed intake. Adding TP in the diet significantly reduced the level of TG, GLU and UN in plasma in the group of HE and LE (p<0.05) . After adding TP, the contents of T-AOC and CAT were significantly increased (p<0.05) , the level of SOD was increased in the group of HE and LE (p>0.05) , while the level of MDA was significantly reduced (p<0.05) . Conclusion:Adding tea polyphenols could improve lactation performance of rats by improving antioxidant capacity of rats, reducing oxidative products and adjusting the levels of lactational hormones.