Abstract: Extracting pigment from Cordyceps militaris, and after qualitative analysis, showed three finger abstortion, the determing this pigment as carotenoid. The results showed that caroten- oid of Cordyceps militaris was sensative to the temperature, and the ions of Fe3 +and Cu2 +had obvious hyperchromic effect on carotenoid, but other metal ions had little effect on the stability of the carotenoid, and H2O2had little effect on its stabilitied.Although it was sensative to HCl, and it was not sensative to NaOH. And light had much effect on its stabilities, during its storing should keep avoid of light.