In order to solve the infrared image registration problem of the monitored exhaust in vehicle exhaust monitoring system, a method of infrared image registration based on double scale search genetic algorithm is proposed. The method takes mutual information as the similarity measure and modify probability formula of crossover and mutation in the traditional genetic algorithm. The proposed double scale search genetic algorithm is used as the optimization algorithm to realize high precision registration of vehicle exhaust infrared image. The obtained root-mean-square error of horizontal translation, vertical translation and rotation angle are 0.0949, 0.0447 and 0.0000, respectively, and the results of experiment with this method are better than other methods and it proves the effectiveness of the proposed method. In comparison to the image registration method based on the adaptive genetic algorithm and ant colony algorithm, and the proposed method has higher precision and better stability. Compared with the Powell algorithm, the proposed method has stronger anti-noise ability and is more suitable for exhaust image registration, which is a good foundation for inversion and calculation of pollution gas concentration.