Transient overvoltage is one of the important factors affecting the stable operation of power grid，and the accurate measurement of transient overvoltageit is of great significance． For this reason，a measuring device for wideband transient electric field is designed based on the measurement method of space electric field effect． Firstly，the principle of measuring the electric field based on non － contact capacitive transformer is introduced． Secondly，the design of its external structure and internal circuit is completed． Finally，under laboratory conditions，power frequency and impulse voltage tests are performed on the developed measuring device． The results show that the measurement error of the proposed measuring device is within 5% ， and its frequency response covers 5 Hz and 5 MHz． It can effectively capture the power frequency voltage and the standard lightning full wave of 1． 2 μs /50 μs．