True-color night vision system was designed to get true color of the targets at night. The theory of the system was analyzed. According to charcteristics of full moon light spectrum, combining the spectral reflected characteristics of typical target and spectrum response soope of S25+, using the principle of cintrast reversion and considering characteristics of visual of human's eyes，the spectrum intersected idea of triple-spectrum true-color night vision was presented in the end. According to the spectrum intersected idea, filters were designed and then their transmittance were measured. Experiment was carried out by the filters and a method to fuse triple-spectrum low-level light images was presented. The result shows that the proposed method could restore the true color of target.