A method for forming a capacitor in a dynamic random access memory, comprising steps of: providing a semiconductor substrate having at least a transistor, whereon an interlayer dielectric layer having at least a first plug is formed so that the first plug is connected to the drain of the transistor; depositing an etching stop layer on the first plug and the interlayer dielectric layer; depositing a first insulating layer on the etching stop layer; forming at least a second plug on the first insulating layer and the etching stop layer so that the second plug is connected to the first plug; depositing a second insulating layer on the first insulating layer and the second plug; forming at least a mold cavity in the second insulating layer so that the aperture of the mold cavity is larger than the diameter of the second plug and there is a deviation between the mold cavity and the second plug; removing the first insulating layer in the mold cavity until the etching stop layer; depositing a first electrode layer to cover the second insulating layer, a sidewall portion of the mold cavity, the second plug and the etching stop layer; removing the second insulating layer so that the first electrode layer forms a single open-ended cavity; and depositing a dielectric layer and a second electrode layer.