The invention relates to a resistive random access memory (RRAM) with amorphous carbon material of a double-layer porous structure and a preparation method of the RRAM. The RRAM comprises an inert metal, a first layer of porous amorphous carbon, a second layer of porous amorphous carbon, and an active metal. The inert metal is a bottom electrode. The first layer of porous amorphous carbon is disposed on the bottom electrode. The second layer of porous amorphous carbon is disposed on the first layer of porous amorphous carbon. The active metal is disposed on the second layer of porous amorphous carbon and is a top electrode. The pore size of multiple pores of the second layer of amorphous carbon is larger than that of multiple pores of the first layer of amorphous carbon. The RRAM and the preparation method eliminate the initializing process and greatly improve the yield of devices. By controlling the nitrogen content and precisely controlling the size of the pores in the dielectric layers, the formation and the fracture of conductive filaments are effectively controlled, and the uniformity in device circulation is improved.