Abstract: In order to improve the electrostatic discharge (ESD) risk assessment method for geosynchronous orbit (GEO) spacecraft, research on flexible antenna sensors for spacecraft ESD radiation detection were carried out in this article. Based on the frequency band characteristics of space ESD radiation electromagnetic wave, the means applied included the three-dimensional electromagnetic field simulation software ANSYSS HFSS, the equivalent technology of rectangular patch antenna, the trapezoidal ground plane technology and the CPW feeder exponential asymptotic technology. Polyimide (PI) was used as the base of the flexible antenna, and its thickness was 0.28 mm. The voltage standing wave ratio (VSWR) was less than 3 in the 300 MHz to 2 GHz frequency band range when the bending radius was 100, 300, 500 mm and no bending, of which the VSWR was less than 2 in the 650 MHz to 2 GHz frequency band range. The electromagnetic pulse (EMP) signal detection performance was measured and analyzed by the ESD simulation test platform. The results show that the designed antenna can detect ESD EMP signal effectively, with the potential to be used for spacecraft ESD fault warning.