Abstract: Response of X-band 4-unit microstrip antenna array to high power electromagnetic pulse is calculated by using the finite difference time domain method and proposed singularity solving technology of conductor edge which maintains high accuracy and computation efficiency. The simulation results show that the maximum response voltage is caused by the superposition of incident pulse in feeding point received by array elements, while the existed mode of wave in the antenna array is different from which motivated in feeding point. Peak response voltage increases as the increase of the angle between incident pulse wave vector and z axis, or the decrease of the angle between incident pulse wave vector in xOy plane projection and x axis. Response spectrum gradually moves to lower frequency band as the increase of the two angles mentioned above.