Abstract: The electric potentials given rise by the charges even distributed in space of pillar regions are calculated by means of the superposition principle of electric potentials. Here we regard the charges distributed in an infinite line as a ＂source charge＂ in two-dimensional plane and consider the charges distributed in pillar regions as assembly of the ＂source charges＂. In complicated cases, the charge distributions can not be expressed by two-dimensional analytic functions, the electric potential may be calculated with computer easily. The characteristics of the electric potentials corresponding to different charge distributions are displayed.

Key words: electric potential, charge distribution, superposition principle of electric potential