Low-light-level(LLL)night vision device is an important optoelectronic equipment,and the operation range is one of its important performance parameters.Aiming at the estimation of operation range for LLL night vision system,three estimation methods are analyzed,which are limiting resolution curve method,restricted photon method and improved restricted photon method.The view range estimation software was programmed with VB language.The experimental results verifies the effectiveness of the estimation model of operation range.