Abstract: Orthogonal experiment was used to optimize the extraction process of carotenoids from the fruiting body of Cordyceps Militaris based on the comparison results of solvent extraction method,ultrasonic assisted extraction method,microwave assisted extraction method and acid heat extraction method,and the antioxidant activity of carotenoids was also detected.The experiment results showed that the acid thermal method was better than other extraction methods,and the optimal extracting conditions of acid thermal method were: the concentration of hydrochloric acid of 1 mol / m L,the usage of hydrochloric acid of 20 m L per gram fruiting body,time of digestion of30 min,time of thermal treatment of 5 min.The yield of carotenoids reached to 1387μg / g.Anti- oxidation experiment results showed that carotenoids from fruiting body of Cordyceps Militaris had better antioxidant ability and the ability was increased with higher concentrations. At concentration of 4 mg / m L,the carotenoids could decrease96.57% of DPPH radicals and value of EC50 of the Chelating ability on iron ions was 3.26 mg / m L. In addition,the carotenoids of Cordyceps Militaris also revealed better reducing capacity.