Objective: To analyze the level of psychological birth trauma (PBT) and its influencing factors among puerperae with high-risk pregnancy, so as to provide a reference for enhancing their mental health. Methods: sing a convenience sampling method, puerperae with high-risk pregnancy who delivered at the obstetrics department of a tertiary hospital in Guiyang City between December 2024 and June 2025 were recruited as the study subjects. Data on sociodemographic characteristics and clinical information were collected through questionnaire surveys. The level of PBT was assessed using the Psychological Birth Trauma Scale, while perceived social support, resilience, and flourishing were measured with the Perceived Social Support Scale, Resilience Scale, and Flourishing Scale, respectively. Multiple linear regression model was employed to analyze the influencing factors for PBT among puerperae with high-risk pregnancy. Results: A total of 508 puerperae with high-risk pregnancy were surveyed, with an average age of (31.40±4.51) years. Among them, 259 held a bachelor's degree or above (50.98%). The scores for PBT, perceived social support, resilience, and flourishing were (71.71±14.76), (56.92±8.68), (22.38±4.46), and (32.19±7.78) points, respectively. Multiple linear regression analysis indicated that puerperae with high-risk pregnancy who living in a stem family (β' =0.104), undergoing emergency cesarean delivery (β' =0.180), having pregnancy-related comorbidities or complications (β' =0.132), having a history of adverse pregnancy outcomes (β' =0.075), poor sleep quality in the third trimester (β' =0.365), lower score for perceived social support (β' =-0.123), lower score for resilience (β' =-0.094), and lower score for flourishing (β' =-0.186) were statistically associated with higher levels of PBT. Conclusions The level of PBT among puerperae with high-risk pregnancy was moderate. Family structure, mode of delivery, pregnancy-related comorbidities or complications, history of adverse pregnancy outcomes, sleep quality in the third trimester, perceived social support, resilience, and flourishing were factors affecting the level of PBT.