Abstract: The role and status of star sensor and simulator in the determination of spacecraft spatial attitude were researched, as well as the basic working principle. According to the colorimetry theory and formula, how to form various synthesis light source color with red-green-blue(RGB) color was analyzed, and the mathematical equation was deduced between the RGB color coordinates and brightness coordinates with a synthesized source chromaticity. On the basis of theoretical research, a kind of static multi-star simulator circle controlled light source which used full-color RGB lamp as the light emitting device was put forward. Under the condition of laboratory, the output light power and wavelength stability of the circle controlled light source system were tested in experiments, and the experimental results were given. The experimental results showed that the short-term stability of the light sources was always better than 1/1 000.