A memory device and an operating method for a resistive memory cell are provided. The memory device includes the resistive memory cell. The resistive memory cell includes a first electrode, a second electrode and a memory film between the first electrode and the second electrode. The first electrode includes a bottom electrode portion and a sidewall electrode portion extending upwardly from the bottom electrode portion and between the memory film and the bottom electrode portion. A width of the sidewall electrode portion and a width of the memory film are smaller than a width of the bottom electrode portion.