Objective To investigate and analyse the clinical associated risk factors which affect the placenta praevia, providing theoretical basis for early prevention and treatment of this disease. Methods Clinical data of 420 cases, diagnosed as having placenta praevia, were collected to establish database, and logistic regression analysis was conducted to analyze the clinical associated risk factors. Results The number of cesarean section (OR=2.656, 95%CI: 1.457-5.536 ), twin and multiple pregnancy (OR=2.325, 95%CI: 1.643-5.673), endometritis (OR=4.646, 95%CI: 1.642-6.534) , smoking (OR=3.453, 95%CI: 1.653-7.562), number of abortion (OR=2.267, 95%CI: 1.785-6.545), were closely related to placenta praevia and placenta praevia can lead to adherent placenta, placenta accreta, postpartum hemorrhage, premature birth, stillbirth and other adverse pregnancy outcomes. Conclusions Uterine incision delivery, smoking, abortion, multiple pregnancy, and endometritis are related risk factors of placenta praevia.