A method for forming a capacitor array structure includes the following steps: providing a substrate, a capacitor contact being exposed on a surface of the substrate, and the substrate including an array region and a peripheral region; forming a bottom supporting layer covering the substrate and the capacitor contact, the bottom supporting layer having a gap therein; forming a filling layer filling the gap and covering the capacitor contact and the surface of the bottom supporting layer, a thickness of the filling layer located at the peripheral region being larger than that of the filling layer located at the array region; forming supporting layers and sacrificial layers alternately stacked in a direction perpendicular to the substrate; forming a capacitor hole; sequentially forming a lower electrode layer on an inner wall of the capacitor hole.