Correlative interferometer could obtain unknown radiation source electromagnetic wave phase information, to calculate the arrival angle with the relevant algorithm, which had been widely used in engineering. However, the phase of the antenna was often distorted by platform impact, which leaded to the deviation of direction finding. Based on the interferometer system, the genetic algorithm was used to optimize the baseline and weight of the direction finding system. Combined with typical examples, the change of direction finding error before and after optimization was analyzed and compared. It was proved that this method could improve the direction finding precision, and the proposed method had practical significance fore airborne direction finding.