To explore the relationship between the levels of interleukin (IL)-17 and high mobility group protein B 1 (HMGBl) in peripheral blood of women with unexplained recurrent spontaneous abortion (URSA) and their Th17/Treg cells value. Methods:60 women with URSA (in study group) and 60 healthy pregnant women (in control group) from March 2019 to March 2020 were selected retrospectively. The levels of HMGBl,  RAGE,  Thl7,  Treg,  IL-6,  IL-10,  IL-17,  and transforming growth factor (TGF)-β, and the value of Thl7/Treg of the women in the two groups were detected. The relationship between IL-17 and HMGB1 levels in peripheral blood of the women and their Th17/Treg value was analyzed. The predictive value of the IL-17 and HMGB1 levels for URSA was also analyzed. Results: The levels of Th17 cells, HMGB1, IL-6, and IL-17, and the value of Th17/Treg of the women in the study group were significantly higher than those of the women in the control group, while the levels of Treg cells, TGF-β, and IL-10 of the women in the study group were significantly lower. The levels of Il-17 and HMGB1 of the women were positively correlated with their Th17 and IL-6 levels and their value of Th17/Treg, but were negatively correlated with their levels of Treg, TGF-β, and IL-10 (all P＜0.05). Receiver operating characteristic analysis showed that IL-17 and HMGB1 levels had certain accuracy for predicting URSA (AUC=0.790, 0.980), with the sensitivity (50.0%, 95.0%) and the specificity (100.0%, 99.5%). The AUC, the sensitivity, and the specificity of the combination of IL-17 and HMGB1 levels for predicting URSA were 0.977, 96.7%, and 91.7%, respectively. Conclusion: The levels of IL-17 and HMGB1 in the peripheral blood of the women with URSA are abnormally high, which are positively correlated with the Th17/Treg value. Therefore, the prediction and diagnosis of URSA by the IL-17 and HMGB1 levels in blood has certain reference value.