To analyze the correlation between vaginal microecological related indexes and intrauterine adhesion (IUA) and the severity of IUA. Methods：The clinical data of the women who had accepted hysteroscopy from June 2018 to June 2020 were selected retrospectively, which included women with IUA in study group and women with normal uterine cavity in control group. According to the severity of IUA, the women in the study group were further divided into group A (women with mild IUA), group B (women with moderate IUA), and group C (women with severe IUA). The vaginal microecological examinations before hysteroscopy of the women in these groups were conducted. Results: The percentages of Ⅰor Ⅳ class of vaginal microecological bacteria concentration, Ⅰor Ⅳclass of flora diversity, the lactobacillus not in dominant bacteria, PH>4.5, trichomoniasis, and bacterial vaginosis, and the positive rates of hydrogen peroxide (H2O2), acetyl amino glycosidase enzymes (NAG), and saliva acid glycosides enzyme (SNA) of the women in the study group were significant higher than those of the women in the control group (P＜0.05). The fungicidal detected rate, and the positive rates of leucocyte esterase (LE) and β-glucuronidase (GUS) of the women had no significant different between the two groups (P＞0.05).Ⅰor Ⅳ class of bacterial diversity, bacterial vaginosis, positive H2O2, and positive SNA were the independent influencing factors of IUA (P＜0.05). The percentages ofⅠor Ⅳ class of bacterial diversity, the lactobacillus not in dominant bacteria, PH>4.5, and bacterial vaginosis, and the positive rates of hydrogen peroxide (H2O2), acetyl amino glycosidase enzymes (NAG), and saliva acid glycosides enzyme (SNA) of the women in group C were significant higher than those of the women in group A and group B (P＜0.05), but which of the women had no significant different between group A and group B. There were no significant differences in the concentration of vaginal flora, the detection rate of trichomonas, and the positive rate of NAG of the women among group A, group B, and group C (P＞0.05). Ⅰor Ⅳ class of bacterial diversity, bacterial vaginosis, and positive SNA were the independent influencing factors of severe IUA (P＜0.05). Conclusion: Vaginal microecological imbalance of the women is closely related to their occurrence of IUA, especially severe IUA, so which should be paid close attention to in clinical practice.