Аннотация:The system of equations describing nonstationary cooling of two-temperature plasma behind the shock wave front is presented. The physical processes inside the front are discussed. The flow motion is converted into heat energy of heavy particles (ions and atoms) in the wide region of flow parameters, while electrons are heated mainly by comparatively weak adiabatic compression. The calculations of emission-line absolute intensities, Balmer decrement, and stratification of hydrogen, nitrogen, oxygen, and sulphur line intensities are compared with the available supernova remnant observations.