The present invention is to provide a multiple phases switching circuit which is operable with a multiple phase signal generator and a succeeding circuit. The multiple-phase signal generator generates N multiple-phase clock signals. Phases of the multiple-phase clock signals are different. The multiple phases switching circuit comprises an alternative signal generator and a multiplexer. The alternative signal generator outputs an alternative signal according to an up/down switching signal. The multiplexer is coupled to the alternative signal generator for receiving the multiple-phase clock signals and proceeding a glitch/spike preventing process according to the alternative signal so as to output a target clock signal to the succeeding circuit.