Scene matching real-time image synthesis plays an important role in simulation of aircraft navigation and performance evaluation of scene matching algorithm. The factors affecting low-light level (LLL) imaging including the change of illumination, meteorology, the characteristics of ICCD camera and the ground spectral reflectance are investigated. Mathematical models of LLL scene simulation are established, including ground reflectance model, ICCD camera model, atmosphere transmission model and noise model. The contrast difference between daytime image and LLL image is studied and a LLL image simulation scheme is proposed. Then a whole real-time LLL image matching synthesis system oriented to ICCD camera is developed using the computing kernel of LOWTRAN7. Simulation result shows this scheme is valid.