The E-field of pulse line ion accelerator （PLIA） is unique with high frequency （~MHz）, large magni- tude （~MV/m）, and limited measuring space （~cm）. The integrated optical E-field sensor （IOES） has remarkable advantages and has been used for PLIA E-field measurement. Firstly, the transfer function of the IOES has been calibrated to ensure measurement accuracy. The time-domain response illustrates that the sensor has a fast dynamic performance to effectively follow a 4 ns rising edge. Then, the E-field distribution along the axis and near the insula- tor surface of the PLIA was measured, showing that propagation of the E-field is almost lossless and the E-field near the insulation surface is about 1.1 times larger than that along the axis, which is in accordance with the simulation result.
