The invention provides an RRAM and a manufacturing method thereof; the RRAM comprises upper and lower electrodes, and a double-resistance metal oxide layer sandwiched between the two electrodes. In the prior art, the RRAM process is not inserted into the production process of the semiconductor devices, so that the manufacturing process is complex and inefficient; besides, the double-resistance metal oxide layer or the lower electrode can be exposed in the oxygen plasma in the ashing process during the RRAM process of the prior art, so that the components or thickness of the double-resistance metal oxide layer are hard to control so as to result in the degradation of RRAM quality. The lower electrode of the RRAM is a metal plug or a metal lead wire arranged in a lower metal layer; the upper electrode is connected with the educed lead wire of the upper electrode of a first or upper metal layer; the RRAM manufacturing method enables the RRAM process to be inserted in the production process of the semiconductor devices and adopts a hard mask layer to avoid the double-resistance metal oxide layer or the lower electrode being exposed in the oxygen plasma in the ashing process. The invention can improve the RRAM quality and manufacturing efficiency, simplify the manufacturing process and reduce the manufacturing costs.