〔Abstract〕 Objective To explore the positive expression of CD138 in infertility patients caused by chronic endometritis and its predictive value for pregnancy outcome of infertility patients caused by chronic endometritis. Methods 80 infertility patients treated at Huizhou Huiyang Maternal and Child Health Hospital from May 2019 to January 2021 were selected. All patients underwent endometrial biopsy and were divided into case group with 22 cases and negative group with 58 cases.According to the results of endometrial hematoxylin eosin staining. Immunohistochemical examination of CD138 in endometrium was performed in both groups, and the positive rate of CD138 in each group was compared. At the same time, the patients in the case group were treated with standardized antibiotics. The patients in both groups were followed up for more than 6 months, followed up the success of pregnancy, and analyzed the positive rate of CD138 in the successful pregnancy. Results The positive rate of CD138 in case group was 95.45%, which was significantly higher than that in negative group 3.45%, the difference was statistically significant (P < 0.05). Follow-up for more than 6 months, there were 3 cases of intrauterine pregnancy in the case group after standard antiinfection treatment, and 21 cases of intrauterine pregnancy in the negative group after treatment, among which the pregnancy success rate of CD138-positive patients was significantly lower than that of CD138-negative patients, the difference was statistically significant (P < 0.05). Conclusion The positive rate of CD138 in endometrium of patients with chronic endometritis complicated with infertility is high, and the success rate of intrauterine pregnancy of patients with chronic endometritis complicated with infertility with positive expression of CD138 is low. Therefore, it is expected to diagnose chronic endometritis complicated with infertility by detecting CD138, predict its pregnancy outcome, and provide guidance for clinical treatment. In addition, actively treating endometritis and turning CD138 from positive to negative is conducive to improving the success rate of pregnancy.