Abstract: An operation method of a resistive random access memory (RRAM) cell is provided, wherein the RRAM cell includes a variable impedance element and a switch element connected in series. The operation method includes the following steps. When the switch element is turned-on, a writing signal is provided to the variable impedance element to set an impedance of the variable impedance element. In a first period, the writing signal is set to a first writing voltage level to transmit a first electrical energy to the variable impedance element. In a second period, a second electrical energy is transmitted to the variable impedance element by the writing signal. The second period is subsequent to the first period, the first electrical energy and the second electrical energy are greater than zero, and the second electrical energy is smaller than the first electrical energy.