Lu, Y. Feng, G. Hu, T. Jiang, J. Tu, X.D. Xiong, Y.Q. JACoW Publishing Geneva, Switzerland 2226-0366 978-3-95450-194-6 10.18429/JACoW-LINAC2018-MOPO119 English 246-249 MOPO119 cavity simulation coupling controls network Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-LINAC2018-MOPO119 http://jacow.org/linac2018/papers/mopo119.pdf The resonant cavity plays a great role in the linear accelerator. An accurate measurement of the cavity field distribution is very important to design linear accelerators. A fully computer controlled bench for the electric field distribution has been developed in this context. Based on the perturbation theory, the acquisition of the resonant frequency shift is proportional to the square of E (electric field). In order to verify the reliability of the test bench, a standard cylindrical cavity has been tested in this measurement system. The simulation by HFSS (High Frequency Structure Simulator) and the practice will be both presented in this paper. And the result demonstrates that, because of its high concentricity, the automated test bench achieves high precision in measuring the distribution of electric field.