The present invention belongs to the technical field of semiconductor memories, in particular to a metal oxide semiconductor (MOS) transistor structure integrated with a resistance random access memory (RRAM). The MOS transistor structure comprises a MOS transistor and a RRAM formed on a substrate, wherein a gate dielectric layer of said MOS transistor extends to the surface of a drain region of said MOS transistor; and the part of the gate dielectric layer on the surface of the drain region of said MOS transistor faults a resistance-variable storage layer of said RRAM. In this invention, the high-quality dielectric layer of the MOS transistor and the resistance-variable storage layer of the RRAM are obtained by primary atomic layer deposition which integrates the RRAM and MOS transistor together without increasing steps. This process is simple and can combine the shallow trench isolation or field oxygen isolation and ion implantation or diffusion of source electrode and drain electrode to make integration convenient.