Intrauterine adhesion (IUA) is one of the most common diseases of the reproductive system. Due to the high postoperative recurrence rate of IUA, it is crucial to identify the possible causes of pathogenesis and recurrence of this disease. In the present study, a high‑throughput sequencing approach was applied to compare the vaginal microbiota between healthy women [healthy vaginal secretion (HVS) group] and patients with IUA [intrauterine adhesion patients' vaginal secretion (IAVS) group]. The results indicated that IUA had little effect on the number of vaginal bacterial species. However, at the phylum level, patients with IUA had a significantly lower percentage of Firmicutes and a higher percentage of Actinobacteria than the HVS group (P<0.05). At the genus level, ~50% of patients with IUA were found to have a marked reduction in probiotic Lactobacillus accompanied by an overgrowth of pathogenic Gardnerella and Prevotella (P<0.05), and the Principal Coordinates Analysis confirmed that 10/20 samples in the IAVS group were scattered far away from the HVS group. Therefore, it was concluded that the interaction between IUA and vaginal microbiota greatly influenced the vaginal diversity of patients with IUA. In order to increase the recovery rate and lower the recurrence rate of IUA, increasing the vaginal Lactobacillus population should be considered.