White LEDs may be used as light source, however, the thermal dissipation of powerful white LEDs which comes along with the high luminous flux is a great trouble. The most of commercial white LEDs are made of blue chip and fluorescence powder,and the powder is sensitive to temperature. With the rise of temperature, the corresponding wavelength of the powder will be excursion. This paper demonstrated the possibility of LEDs being used as light source when driven by pulse. The results show that powerful white LED is better at thermal dissipation when driven by this kind of energy input. The author has given explanation at the end of the article.