The extraction and development of polysaccharide was researched to multipurpose use of cordyceps militaris culture medium with wheat. This article studied the optimum extraction process of coarse polysaccharide in cordyceps militaris culture medium through the orthogonal factor experiment on hot reflux water on the base of single factor experiment on hot reflux water and ultrasonic extraction，researched the antitumor activity of polysaccharide purified by cordyceps militaris culture medium by MTT method. The results showed that hydrothermal refluxing extraction is better than supersonic water extraction on the basis of the results of single factor experiment. The results of orthogonal test showed the optimal technological conditions for the extraction conditions of coarse polysaccharide of were as follow：extracting temperature was 100 ℃， material-water ratio was 1∶25，extracting times was three and time was 90 min. The primary and secondary relationships of four Factors influencing the efficiency of extraction coarse polysaccharide are：extraction temperature > extraction time > extraction times > solid-liquid ratio. The coarse polysaccharide yield increased with the increasing of concentration of alcohol. The MTT test found the polysaccharide purified by different processing has inhibitory effect on the liver cancer cells，5 mg/mL concentration of polysaccharide，effect time for 72 h，inhibition rate of polysaccharide gained by degreasing and deproteinization from culture medium of Cordyceps militaris for hepg2 cells can reach 83.02%，inhibition rate of polysaccharide gained by degreasing medium for hepg2 cells can reach 75.39%，inhibition rate of polysaccharide gained without degreasing and deproteinization for hepg2 cells can reach 30.61%，purified polysaccharide showed higher inhibition rate. The polysaccharide extracted by cordyceps militaris fruiting body with 100 ℃ hot reflux water ，5 mg/mL concentration of polysaccharide，training after 72 hours，the inhibition rate reached 92.974% on Hepg2 cell，there was no significant difference compared with SB，but was significant difference compared with polysaccharide gained by degreasing and deproteinization from culture medium of Cordyceps militaris.