To investigate the correlation between chronic endometritis (CE) of infertile patients and their outcomes after frozen embryo transfer (FET). Methods: A total of 430 patients who underwent artificial cycle frozen embryo transfer from January 2020 to June 2021 were selected as research subjects retrospectively. According to the results of endometrial biopsy, these patients were divided into group A (85 patients with CE) and group B (345 patients without CE). The patients in group A were given antibiotic treatment, and the patients in group A were divided into group A1 (65 patients with CE negative conversion) and group A2 (20 patients with CE positive persistence) according to the outcomes of the patients after antibiotic treatment. The general data, the endometrial morphological indicators on the day of luteal transition, such as endometrial thickness, endometrial volume, and endometrial morphotype, the values of uterine artery hemodynamic parameters, such as peak systolic velocity (PSV), pulsatility index (PI), and resistance index (RI), and the outcomes of FET of the patients were compared among group A1, group A2, and group B. Logistics regression analysis was used to analyze the correlation between the positive CE of the patients and their FET failure. Results: The endometrial thickness (0.92±0.09cm), the endometrial volume (5.40±0.23ml), the ratio (15.0%) of endometrial type A, and the value of PSV (32.04±1.23 cm/s) of uterine artery of the patients in group A2 were all significantly lower than those of the patients in group A1 and group B (P＜0.05). The values of PI (2.53±0.21) and RI (0.94±0.11) of uterine artery of the patients in group A2 were significantly higher than those of the patients in group A1 and group B (P＜0.05). There were no significant differences in the endometrial thickness, the endometrial volume, the ratio of endometrial type A, and the values of PI, RI, and PSV of uterine artery of the patients between group A1 and group B (P>0.05). Logistic regression analysis showed that positive CE of the patients was an independent risk factor of their FET failure (P＜0.05). Conclusion: CE of the infertility patients is associated with their FET failure, which may affect the clinical pregnancy rate by affecting their endometrial receptivity. So, the effective treatment of CE of these patients maybe lead to better FET outcomes.