Aiming at the problem that the interference beam of EW phased array can't aim at the target due to the error of the measurement result of the warning receiver, this paper proposes a wide beam-based EW phased array operation mode, designs the array direction pattern that can cover the interference space domain by using genetic algorithm, and analyzes the jamming efficiency of the wide beam. The results show that the electronic warfare phased array based on wide beam can still work normally and improve the reliability of the equipment under the abnormal conditions such as large direction finding error, false alarm and type identification error of the warning receiver. In addition, to solve the problem of widening the burn through distance caused by the decrease of the transmission gain of wide beam, some suggestions are put forward to improve the power of the array channel and switch the working mode according to the distance.