Based on the calculation about intervalley scattering rates in ZnS, intervalley transfer process in ZnS-type thin-film electroluminescent devices is investigated through Monte Carlo simulation. The transient process of intervalley transfer, the influence of electric field on intervalley distribution and the electron kinetic energy distributions in different valleys are obtained. We propose that high valley could store energy. These results could be used as the basic data on the study of electroluminescent process.