IEC 62228-5 requires electrostatic discharge (ESD) damage test of common-mode chokes (CMCs) used in EMC evaluation of automotive Ethernet transceiver ICs. However, with the recommend ESD damage test board in IEC 62228-5, mounting and re-mounting of a jumper or 0 Ω resistor in the S-parameter measurement route (microstrip lines) are needed, which may cause uncertainty in the S-parameter measurement results. In this paper, we proposed and validated an improved ESD damage test board which ensures both S-parameter measurement and ESD application.