Objective: To investigate the effect of placenta previa attached to cesarean scar for adverse pregnant outcomes in patients with or without placenta accreta spectrum disorders (PAS). Methods: The clinical information of patients with cesarean section history and placenta previa during the perioperative period at Peking University First Hospital from January 1st, 2015 to December 31st, 2020 were collected retrospectively. There were 53 cases without PAS and 172 cases with PAS, 153 cases with abnormally invasive placenta (containing placenta increta and placenta percreta) and 72 cases without PAS or with placenta accreta. The pregnant outcomes including rate of postpartum hemorrhage, transfusion, hysterectomy between the above groups were compared. Multivariate analysis was performed to study the factors significantly associated with PAS. Results: Pregnant women with PAS were at higher risk of adverse pregnant outcomes than those without PAS. Patients with PAS had higher incidences of hysterectomy [12.2% (21/172) vs 0(0/53); P=0.005], postpartum hemorrhage [60.5% (104/172) vs 5.7% (3/53); P0.01). Conclusions: Placenta previa attached to cesarean scar without PAS or with placenta accreta could not act as the factor of predicting adverse pregnant outcomes in clinic. Placenta previa attached to cesarean scar with placenta increta or placenta percreta could increase the risk of adverse pregnant outcomes.