Luminescence of lead azide Pb(N3)2 crystals in the range of 400–1000nm is studied experimentally. As the detonation of lead azide is initiated by an electron accelerator pulse, the onset of the mechanical destruction is preceded by intensive luminescence and a rapid growth of the conductivity. Theoretical investigation of the electronic structure of a lead azide crystal was done by means of the Hartree–Fock method for a periodic system. Detailed comparative analysis of the calculated density of states and experimental luminescence spectrum of lead azide suggests that decomposition proceeds by a chain reaction mechanism. A model of the pre-explosive luminescence based on the hypothesis of the quasi-local state formation in the valence band is proposed. The position of a possible energy level of the state in the valence band is predicted.