The invention provides a method for manufacturing a memory unit of a phase-change random access memory. The method comprises the following steps: (S501), providing a front-end device structure which comprises a bottom electrode, a phase-change resistance layer and an insulation layer, wherein the surface of the phase-change resistance layer is exposed on the surface of the insulation layer; (S502), performing ion implantation on the surface of the phase-change resistance layer; (S503), forming etching stopping layers on the surfaces of the phase-change resistance layer and the insulation layer; (S504), forming dielectric layers on the etching stopping layers; (S505), etching the dielectric layers and the etching stopping layers untill exposing the surface of the phase-change resistance layer, thereby forming an opening right above the phase-change resistance layer in the dielectric layers and the etching stopping layers; and (S506), filling a metal material in the opening, thereby forming a top electrode. By adopting the method, the etching loss of a phase-change material which is caused by uneven thickness of the etching stopping layers during a process of etching the dielectric layers can be reduced.