Four experimental diets were formulated to contain 0, 0.05%, 0.10% and 0.15% composite plant extract, which were mainly extracted from coarse old tea, sweet orange, orange peel, purslane, wild chrysanthemum flower, buckwheat. Triplicate groups each with 20 Trionyx sinensis (initial body weight, 42.47±1.00 g) were fed one of the experimental diets for 30 d. The results showed that, compared with the control group, growth rate and specific growth rate significantly increased in 0.05% addition group (P<0.05), and significantly reduced in 0.15% addition group (P<0.05). There was no obvious change in growth rate and specific growth rate in 0.10% addition group compared to the control (P>0.05). The difference of the contents of liver water, body water and body crude protein among groups reached no statistical significance (P>0.05), but compared with the control group，the contents of liver fat in composite plant extract addition groups were significantly decreased (P<0.05), and the contents of body fat in 0.05% addition groups increased significantly (P<0.05) but showed no significant change (P>0.05) in the other two addition groups. The content of serum total protein (TP) and glucose (Glu), the activity of apartate amino–transferase(AST) and alkaline phosphatase(AKP) among groups showed no statistically significant difference (P＞0.05), but compared with the control group, the contents of serum urea and the activities of serum lactic acid dehydrogenase (LDH) in addition groups reduced significantly (P<0.05); the activities of serum superoxide dismutase (SOD) in addition groups significantly increased(P<0.05); the activities of lysozyme (LZM) increased significantly (P<0.05) and the contents of malondialdehyde (MDA) reduced significantly (P<0.05) in 0.10% addition groups, the activities of LZM and MDA in the other two addition groups showed no statistically significant difference (P>0.05). Based on these results, adding 0.05% the composite plant extract in Trionyx sinensis diet enhances the growth performance and improves the antioxidant and immune capacity of Trionyx sinensis.