Abstract: The present paper deals with both the statistical study and the computer simulation of sporadic E-layers at mid-latitude regions. The Fourier transformation of the foes sequence shows that the observational data have a strong 24 h and 12 h periodic component, which means strong correlation of Es with the atmospheric tides. The sporadic E occurrence has one peak at higher latitudes while has double peaks at lower latitudes, which suggests that the sporadic E occurrence is associated with the diurnal and semi-diurnal tides. The simulation work is based on the continuity equation and momentum equation. Method of characteristic curve is adopted. According to the widely studied wind shear theory, simulation for the convergence of metal ions to form a thin layer induced by the tidal wind has been carried out. In conclusion, the strong correlation between the sporadic E-layers and the tide is confirmed not only from the statistical analysis of observational data but also from the computer numerical simulation work.