Abstract:Taking the Flammulina velutipes wast stalk as research materials，using Paecilomyces militaris as the fermentation strain，the waste stalk of F.velutipes was bi-directional solid-state fermented.The changes of polysaccharides，cordycepin，cordycepic acid，protein and amino acid and total reducing ability and the ability to scavenge free radicals of F.velutipes with fermentation time were studied.The results showed that there was a peak-to-valley change in fermented product，and the content of the substance increased gradually with the increase of time in the middle of the fermentation.Compared with the control group，the main components and antioxidant capacity increased significantly，both of which were significant difference.The fermentation time of maximum various active substances was slightly different.The content of polysaccharides，cordycepin and cordycepic acid was the highest at 28 d after fermentation by P.militaris，which were 717.68 mg/g，90.9 μg/g and 25.6 mg/g，respectively，1.92 times，90.9 times and 2.34 times of the control group.The contents of protein and amino acid reached the highest at at 21 d and 24 d，396.6 mg/g and 230.88 mg/g，respectively，which were 2.39 and 4.52 times of the control group.The total reduction capacity of the fermented mycelium reached the highest at 21 d-28 d，and was basically stable.The DPPH free radical scavenging ability of the fermented product of F.velutipes was the highest at 28 days，reached 72.37%，which was 59.5%higher than that of the unfermented.