Global distribution of electric potential, fields and currents in the atmosphere are calculated analytically under a given ionospheric electric potential distribution. The results show that the electric potential of ionosphere at an altitude of 100 km can map down to lower than 25km without obvious attenuation in an atmospheric electric conductivity which increases exponentially with altitude. The region with strong electric field is mainly in the lower atmosphere with altitudes below 20km, where the vertical components are 4-orders of magnitude larger than the horizontal components. The electric fields in middle and upper atmosphere are relatively weak, and the vertical components are at the same order of magnitude as horizontal components. An analytic method is proposed to calculate the influence of topography on atmospheric electric field.