Abstract: Presents a new kind of operator for edge detection-the median nonlinear Laplacian operator based on the analysis of both linear and nonlinear Laplacian operators.The new operator is nondirective and can maintain the detected edge while removing the noise.Another nonlinear edge extraction operator-the grey flatting dian nonlinear Laplacian(FMNLLAn)operator is also developed bed on the above discussion.The latter operator possesses higher accuracy on edge detection.Both have been proved through experiments.