Abstract: During in orbit operation, spacecraft will interact with space plasma and high-energy electrons to produce electrostatic discharge (ESD) effects, threatening the safety of spacecraft. Based on the spectral characteristics of electromagnetic pulse signal generated by spacecraft ESD, in this paper, a flexible antenna sensor was designed, which combined a flexible planar spiral antenna with an Archimedes spiral antenna. The electromagnetic pulse sensing part had a diameter of 144 mm and a thickness of 0.35 mm. The simulation results of ANSYS HFSS software show that, under the conditions of antenna bending radii of 0 and 150mm respectively, in the frequency band range of 50 MHz to 3 GHz, the VSWR is less than 2, showing that the antenna radiation is good. The measurement of the ESD detection performance shows that the flexible antenna sensor can effectively receive the electromagnetic radiation pulse signal before and after bending. This study may be used for spacecraft ESD detection and has practical engineering significance.