Objective To explore the correlation between circadian rhythm of blood pressure and placental abruption in patients with pregnancy-induced hypertension, and to provide a clinical reference. Methods A total of 315 patients with pregnancy-induced hypertension admitted to Guangzhou Women and Children’s Medical Center from January 2018 to December 2022 were selected for retrospective analysis. According to whether placental abruption occurred, the patients were divided into the placental abruption group (71 cases) and the non-placental abruption group (244 cases). Clinical data and 24 h ambulatory blood pressure monitoring data of the two groups were collected, the blood pressure circadian rhythm types of the two groups were compared, and the correlation between 24 h ambulatory blood pressure and placental abruption was analyzed. Results The rate of cesarean section in the placental abruption group was higher than in the non-placental abruption group (P<0.05). The 24 h mean arterial pressure (MAP), night MAP, 24 h mean diastolic blood pressure (mDBP), daytime mDBP, night mDBP, morning peak, and minimum blood pressure of patients in the placental abruption group was higher than those in the non-placental abruption group (P<0.05). The blood pressure circadian rhythm of the non-placental abruption group were mainly divided into arytenoid and non-arytenoid, and the placental abruption group were mainly divided into non-arytenoid and reverse arytenoid. There were statistically signi?cant differences in the composition and distribution of blood pressure circadian rhythm between the two groups (P<0.05). Spearman correlation analysis showed that 24 h MAP, night MAP, 24 h mDBP, day mDBP, night mDBP, morning peak, and minimum blood pressure were positively correlated with placental abruption (P<0.05). Conclusion The change of the circadian rhythm of blood pressure is correlated with placental abruption in patients with pregnancy-induced hypertension, which needs clinical attention.