A novel single-channel blind separation algorithm for permuted defocus blurred image is proposed based on parameter estimation in this paper.The defocus blur radius is estimated by the characteristics of permuted image in the frequency domain

and then the permuted image is restored by performing the Lucy-Richardson(L-R)blind restoration method.The ringing effect of restored image is measured by defining the sum of absolute pixel gradient

and the permutation mixing matrixes can be accurately estimated by classifying the ringing effect of each sub-block

thereby separating the source images.Simulation results show that the proposed algorithm is able to achieve better separation efficiency for the permuted defocus blurred image with various permutation operations and a better performance on the robustness against Gaussian noise and lossy JPEG compression.