Multiscale decomposition method and fusion rule are two key factors for multifocus image fusion method. The Wsystem of degree k is an orthogonal hybrid function system consisting of polynomials of degree k and piecewise polynomials of degree k. The corresponding Wtransform is an effective multiresolution analysis tool with orthogonality and reproducibility. By combining the multiscale characteristics of Wtransform and multidirection property of the nonsubsampled directional filter bank (NSDFB) transform, a new multiscale and multidirectional transform is proposed in this paper, in which multiscale decomposition is performed by the Wtransform and the multidirectional decomposition is obtained from NSDFB. On this basis, a new multifocus image fusion algorithm is proposed. According to the characteristics of the high frequency coefficients, the often used simplified PCNN is modified, and applied on the fusion rules of the high frequency coefficients. The experimental results show that the proposed fusion method can select pixels from focus areas of the source images and effectively avoid generation of artifacts. The fused image has better visual effect. The objective evaluation index including standard deviation, entropy, average gradient, and spatial frequency of the fused image demonstrate that the proposed method outperforms the fusion methods based on Contourlet transform, NSCT transform and discrete wavelet.