Abstract: To provide the basis for the exploitation and utilization, preparation technology and antioxidant activity of extracts from Astragali mushroom were studied. Based on the single factor experiments, the response surface methodology was employed to optimize the conditions of ultrasonic assisted enzymatic of extract from Astragali mushroom, when the content of amino nitrogen and soluble solids was the evaluation index. The results showed that, the optimum conditions were:Cellulase dosage 0.5%, water-material ratio 12:1 mL/g, ultrasonic time 40 min, ultrasonic temperature 40℃, and pH4.0. Under these conditions, the amino nitrogen content of extract was (0.765±0.12) mg/mL, total flavonoid content was 6.5%±0.25%, and the content of soluble solids was 2.0%. The antioxidant activity of enzymatic extraction (EE) results showed that, with V_C as positive control, the ability of scavenging free radicals of DPPH was the strongest. When the concentration was 600 μg/mL, the clearance ability was significantly higher than V_C at the same concentration. A theoretical basis for the further development and application of Astragalus mushroom was provided.