The main objective of this paper is to develop a model of quantum dot (QD) devices for incident γ radiation detection. A novel methodology is introduced to characterize the effect of γ radiation on QD detectors. In this methodology, we used VisSim environment along with the block diagram programming procedures. The benefit of using this modeling language is the simplicity of carrying out the performance’s measurement through computer simulation instead of setting up a practical procedure, which is expensive as well as difficult in management. The roles that the parameters of fabrication can play in the characteristics of QDs devices are discussed through developed models implemented by VisSim environment. The rate equations of the QD devices under γ radiation are studied. The effect of incident γ radiation on the optical gain, power, and output photon densities is investigated. The implemented models can help designers and scientists to optimize their devices to meet their requirements.