A method of controlling multiple lamps is applied to an illumination system, which includes an input interface, a signal transmitter, a plurality of signal receivers, a plurality of driving devices, and a plurality of lamps. The method includes the following steps: detect a state of the input interface with the signal transmitter; transmits a corresponding signal with the signal transmitter; each of the signal receivers receives the signal and detects a waveform of an AC power source, and each of the signal receivers transmits a corresponding control signal to the corresponding driving device to control the corresponding lamp at a reference point in the following cycle of the waveform of the AC power source.