Abstract:The polysaccharides of Cordyceps militaris were extracted by ultrasonic-microwave synergy method，and the effects on the proliferation of mouse spleen cells were studied.The immunological activity was evaluated.The effects of material size，solid-liquid ratio，ultrasonic power，ultrasonic time，ultrasonic extraction times，extraction temperature，ethanol and concentrate on the extraction rate of Cordyceps militaris polysaccharides were studied by single factor and L18（37）orthogonal test.The results of orthogonal test showed that the ultrasonic power and material particle size had significant effects on the yield of polysaccharides from Cordyceps militaris，and the optimal technological parameters of polysaccharide extraction from Cordyceps militaris were determined：material particle size was 0.150 mm，extraction times was 3 times，microwave power was 400 W，ultrasonic power was 300 W，ultrasonic treatment time was 30 min，extraction temperature was 70 ℃，ratio of material to liquid was 1 ∶40（g/mL），ratio of ethanol to concentrate was 4 ∶1（volume ratio）.Under the optimal conditions，the polysaccharide extraction rate was 6.28%.The mouse spleen cell proliferation test showed that the polysaccharide extracted from Cordyceps militaris could promote the proliferation of mouse spleen cells at a certain dose，indicated that the polysaccharide of Cordyceps militaris had immunomodulatory activity.