Abstract: In order to study the effect of Astragalus membranaceus extractive on the antioxidant function of Carassius auratus, the optimum supplemental level of Astragalus membranaceus extractive in Carassius auratus culture was discussed. According to the principle of single factor experiment design, the Carassius auratus were divided into 5 treatment groups with Astragalus membranaceus extractive as the variable and cultured for 8 weeks. After the experiment, the blood and serum of Carassius auratus were collected for detection of serum antioxidant index. The results showed that adding proper amount of Astragalus membranaceus extractive in the production of Carassius auratus could significantly enhance the antioxidant function of the body, and the optimal amount of Astragalus membranaceus extractive was 500～1 000 mg/kg.