Abstract: Frequency selective surface (FSS) radome manufacturing process will produce electrical thickness error. To solve the problem, combined with the hardware and software engineering conditions, a reflection method for measuring and simulating the electrical thickness of FSS radome is proprsed, and the measurement and simulation results are obtained. The variation of the measured data is consistent with the simulation. The proposed method has been validated by the developed transmission thickness measurement system. The research results provide technical support for the electrical thickness detection and electrical performance improvement.