Utilization of the spectrum simulation in many important fields widely, it has made the target spectral simulation technique to be an important development trends. With the rapid development of the application of the LED technology, the LED have the merits of long serving life, high lighting efficiency, rapid responding time, and high wide selection of light band. Consequently, taking the demands of designing for the target spectral scene reproduction systems into consideration, LED with variable light bands as the light source, and performs Gauss Curve calculation to fit spectra in scene via Matlab software, and therefore serving as the criteria to selection of LED. Meanwhile, the system of driving a light source applies high performance embedded MCU as the main data processor. The chip for LED is a specific driver chip which was made in TI Corporation. Through analyzing the data collected from the target spectra in scene, then the processor transfers the calculated results to the driver IC (integrated circuit) of LED. The spectrum in scene is reproduced basing on the results. Moreover, this design method can also combine with spectrometer directly to realize the real-time capability of reproduction of the spectra in scene. It has a great potential application in the future.