The changes of nutrients,volatile substances and antioxidant properties during the compound fermentation of Goji juice by Lactobacillus plantarum and Lactobacillus fermentum were investigated with HPLC and HS-SPME-GC-MS.The results showed that lactic acid bacteria grew well in Goji juice,and the pH value was significantly reduced.During the fermentation process,lactic acid bacteria used saccharose,glucose,and fructose as carbon sources to produce acid,and the content of lactic acid,acetic acid and aminobutyric acid were significantly increased,while the content of oxalic acid,malic acid and citric acid were decreased significantly.The composition and content of phenolic substances in Goji juice were significantly changed after fermentation.The content of protocatechuic acid was not detected in unfermented Goji juice,and increased to 40.55 μg/mL after fermentation.The content of catechins,p-hydroxybenzoic acid,3-hydroxycinnamic acid,and myricetin increased by 13.44%,42.40%,170.73% and 12.30%,respectively.Fermentation of lactic acid bacteria changed the composition and content of volatile components in Goji juice.The content of alcohols,acids,and olefins increased,while some substances including aldehydes and ketones decreased,and volatile components such as ethanol,1-hexanol,and linalool were newly produced after fermentation.The antioxidant capacity of Goji juice was significantly improved as well.The DPPH free radical scavenging rate,total reducing power and oxygen radical absorbance capacity increased by 21.42%,14.18%,and 51.75%,respectively.