The principles and features of multiwavelet transform and PCNN are described in brief.Then the algorithm adopted the fusion rule based on PCNN in not only high frequency domain but also low one obtained by multiwavelet decomposition is proposed.In order to verify the effectiveness of proposed rules,the experiments upon visible light image and infrared image are done.Moreover,comparative results of evaluating fusion quality are listed.The experimental results show that proposed image fusion algorithm performs obviously better in enhancing image contrast,reserving image details of the information and increasing the amount of information.