The invention discloses a visible light / long-wave 
infrared broad band spectrum joint focusing 
optical imaging system comprises a 
broad spectrum focusing window, a color separation film, a 
long wave infrared lens group and a visible light lens group. The color separation film and a horizontal 
optical axis form an angle of 45 degrees, and light incoming from the 
broad spectrum focusing window passes through the color separation film and the visible light lens group to image on a visible light sensor. The 
long wave infrared lens group is composed of a first lens, a second lens, a reflector and athird lens from an object space to an image space in sequence, the reflector is parallel to the color separation film, and 
infrared light in 
broad spectrum light passes through the color separation film and the 
long wave infrared lens group to image on a non-
refrigeration detector. A first face of the second lens is a binary surface, a second face of the third lens is an aspheric surface, and systematic heat difference and 
optical aberration are removed through the design of the binary surface and the aspheric surface. The visible light / long-wave 
infrared broad band spectrum joint focusing 
optical imaging system can solve the problem that a single 
wave band is not high in detection accuracy, two wavebands and two lenses have optical 
parallax on imaging, two wavebands are big in imaging aberration, an infrared 
system has heat difference, and two wavebands need focusing mutually.