Abstract: A new image enhancement method based on Quad-tree Complex Wavelet Packet Transform（QCWPT） is presented according to the inter-scale correlation of the high frequency complex coefficient.The noisy image is decomposed into a low frequency approximation sub-image and some high frequency directional sub-images via the QCWPT，which both has shift invariance，good directional analysis ability，and has the ability to analyze the high frequency detail signal carefully.The complex coefficients in the low frequency approach sub-image are retained unchangeably，and the noise complex coefficients in the high frequency directional sub-images are removed by using of a non-Gaussian bivariate model according to the characteristic that the inter-scale correlation of signal complex coefficients is more stronger than it of noise complex coefficients.In high frequency directional sub-images，some complex coefficients correspond to the weak edges pixels are selected out and are enhanced，because their value are big in some directional sub-images but are small in the other directional sub-images.In numerical comparison with various methods ，the presented scheme has higher operational efficiency and outperforms the traditional Dual-tree Complex Wavelet Transform（DCWT），QCWPT and Wavelet Gaussian Scale Mixtures（WGSM） in terms of the PSNR index and visual effects.Experiments also show that the presented scheme can achieve an excellent balance between suppress noise effectively and preserve as many image details and edges as possible.