A reversible sequential element comprises a first logic gate and a second logic gate. The first logic gate includes a first input terminal, a second input terminal, a third input terminal, a first output terminal coupled to the first input terminal, a second output terminal and a third output terminal. The second logic gate includes a first input line, a second input line, a first output line and a second output line. When the first input terminal is set to a first state, the second input terminal is coupled to the third output terminal and the third input terminal is coupled to the second output terminal; otherwise, the second input terminal is coupled to the second output terminal and the third input terminal is coupled to the third output terminal. The third output terminal, second input line and second output line are coupled to each other. The input signal carried on the first input line is set as 0 so that the second output line and the first output line have the same output.