The absorption and photoluminescence spectra of green and red CdSe/ZnS quantum dot/silicon composite films are measured. The results show that the composite films have stable photoluminescence spectra at different excitation wavelengths and the peaks are located at 527 nm and 628 nm wavelengths, respectively. Two white light emitting diodes (WLED) with different structures are prepared by the combination of the quantum dot/silicon composite films with YAG∶Ce ³⁺ yellow phosphors, and their optical properties and surface temperatures are measured under different driving currents. For 350 mA driving current, the surface temperature of WLED II is 26.5 ℃ lower than that of WLED I. The aging test is conducted at 55 ℃ temperature and 55% relative humidity, and the results show that the optical performances of these two WLEDs typically remain the same under different driving currents, indicating an excellent stability.