The TV guidance systems need to detect missile target signals from images in nature fields and complex backgrounds. Based on the different spectral characters between missile targets and backgrounds, the missile target’s spectroscopic detecting method and theory are proposed. And a spectroscopic detecting optical system with dual CCD sensor is designed. Its light-splitter let images including targets enter the primary CCD sensor and background images enter the secondary CCD sensor. Then a background subtraction circuit subtracts the secondary CCD sensor’s image from the primary CCD sensor’s image. The result is an image containing only the missile target information. Experiment result shows that the method is reliable in detecting missile targets from complex backgrounds.<收到修改稿日期2008-03-27