As a key link in image stitching, image registration based on maximum mutual information does not need any preprocess and has a high degree of automation and high registration accuracy, which thus attracted widespread attention. Optimization search in image registration process is easy to fall into local minima leading to the wrong registration parameters. This paper presents a method to build image pyramid based on wavelet transformation and uses swarm intelligence classical particle swarm optimization method to adjust its parameters with the mutual information and multi-resolution series. Experiments show that this method can effectively avoid local minima and can find the optimal registration transformation by finite optimization iterations. Performance of this proposed algorithm is better than the traditional multi-resolution method and its computational efficiency is higher than that of simulated annealing optimization method