The dried Lycium barbarum in Ningxia was used as the main raw material and fermented by compound probiotics. The effects of strains ratio, solid- liquid ratio, inoculum and fermentation time on fermented goji juice quality were studied by single factor test and response surface methodology. The results showed that the optimal fermentation condition was composite probiotics ratio Lactobacillus plantarum ∶ Leuconostoc mesenteroides ∶ Streptococcus thermophiles ∶ and L. bulgaricus = 3∶3∶2∶1, solid-liquid (dried goji ∶ water) ratio 1∶9 (g∶ml), inoculum 5%, and fermentation time 8 h. The lactic acid content in the fermentation broth was 432 mg/100 ml, the viable cell count was 2.3×108 CFU/ml, the total sugar content was 155 mg/100 ml, the total flavonoid content was 0.25 mg/100 ml, the protein content was 0.2 g/100 ml, and the sensory score reached 96. The color of the fermented L. barbarum juice was bright orange, the taste was exquisite and soft, the fermented aroma was strong, with characteristic taste of L. barbarum.