Abstract： Objective:To analyze the clinical features and the diagnostic value of procalcitonin(PCT) and systemic immune-inflammation index(Ⅱ) in pregnancy complicated with community-acquired pneumonia(CAP).Methods:From January 1, 2020 to December 31, 2022, pregnant patients admitted to our hospital were the source of the study, including 102 patients with CAP as the observation group, and A total of 112 healthy pregnant women who were hospitalized and gave birth from June 1, 2022 to December 31, 2022 were selected as the control group. The area under the subject working characteristic curve (AUC) was used to evaluate diagnostic value of procalcitonin (PCT) and inflammation index(Ⅱ) for community-acquired pneumonia in pregnancy.Results:Among 11247 cases, 102 cases (0.91%) were combined with community-acquired pneumonia, the mean age was (30.61±5.31) years, the mean gestational age was (33.60±5.70) weeks, 91 cases (89.22%) in the third trimester (28 weeks and above), 8 cases (7.84%) in preterm labor, and 1 case (0.98%) in low-weight infant. There were 81 cases of cesarean section in observation group (79.41%) and 55 cases in control group (49.11%) (P<0.001). There was no significant difference in age and BMI between the two groups (P>0.05). The body temperature, white blood cells, neutrophils, platelets, C-reactive protein, procalcitonin and inflammatory index in the observation group were higher than those in the control group (P<0.05). The AUC was 95%CI: 0.652(0.382-0.922) for body temperature, 95%CI: 0.692(0.612-0.772) for leukocytes, 95%CI: 0.672(0.623-0.721) for neutrophils and 95%CI for platelets, respectively: 0.601 (0.515-0.687), C-reactive protein 95%CI: 0.653(0.596-0.710), procalcitonin 95%CI: 0.925(0.878-0.972) and inflammatory index 95%CI: 0.845(0.784-0.906), The predictive value of procalcitonin and inflammatory index was high.Conclusion:Procalcitonin and systemic immune-inflammation index have good predictive value in pregnancy complicated with CAP.