Abstract: On the basis of analyzing low-light-level (LLL) TV imaging system, this paper presents conditions required and generation method of LLL scene digital image data suitable for LLL TV imaging system simulation. Focusing on the second generation proximity focusing system and the third generation imager intensifier system, energy gain theoretical model of LLL TV imaging system is derived. Then, main noise sources of the system are modeled by introducing 3D noise model. At last, the assessment method of the degression of image enhancement algorithm on image noise is proposed.Simulative results show that the high frequency information becomes blur after being transfered through the system, signal to noise ratio reduces because of introduction of noise，and image quality and contrast are greatly