A non-contact voltage detecting method and device are provided. The non-contact voltage detecting device includes a discharge lamp having an excitation voltage and a lighting voltage applied thereon, a boost circuit coupled to the discharge lamp for providing an operation voltage to the discharge lamp and a switch circuit coupled to the boost circuit for providing a periodical high-low signal level to control the boost circuit wherein the discharge lamp flickers if there is a relatively high voltage power nearby, while the discharge lamp is extinguished without the relatively high voltage power nearby. In addition, the device is capable of being an illumination source by increasing an input voltage of the boost circuit when it is not used for detecting the high voltage power.