A new kind of UV and IR composite alarm warning system used in ground equipment was proposed to solve the problems of low detecting distances for a UV warning system and high false alarm for a IR warning system. The detecting mechanisms, capturing conditions and effecting distances of the UV warning system were analyzed.Then, a mode for estimating the detecting distance of the UV warning system based on Lowtran was established to calculate the UV warning system’s detecting distance to a solid fuel missile. In consideration of the effect on the detecting distance, a new way based on Gabor for matching the diagnostic image was used to improve the detecting accuracy for distances. Some experiments to validate our theory and detecting mode were carried out,results show that the detecting distance veracity can be controlled below 5%, and the warning distance can be improved from 5 km to 8 km when the void rate is below 1 time per 10 hours. Using the proposed detecting mode, the detecting efficiency of the complex warning system is enormously improved. This detection mode can also be used in other optical detection equipment.