A new approach using the electric field induction to measure the transient and steady-state zero-module voltage in non-solidly earthed overhead lines is presented. The characteristics of the electric field beneath the lines produced by three-phase overhead lines are analyzed， and show that the variation of vertical electric field is basically proportional to the zero-module voltage before and after the fault. So the transient and steady-state zero-module voltage can be measured with this variation. The method for zero-module voltage measurement with a spatial electric field induced by a field sensor consisting of charge-sensitive amplifier and two parallel metal pole plates is proposed. Simulation and experimental results demonstrate feasibility of the method.