Abstract: This paper puts forward a novel algorithm for image edge detection based on gray correlation degree.First,this algorithm decides employing typical non-edge pixel neighboring sequence of gray level as referential sequence,simultaneously regards all pixel neighboring gray level sequence of disposed image as compared sequence,then computes gray correlation of referential sequence and compared sequence using slope correlation degree,finally judges whether a pixel is edge point based on the comparision of the computed gray correlation and the threshold value.To test this new algorithm the authors make experiments and the result shows this algorithm can gain more precise edge pixel than some traditional methods,futermore it can tolerate some noise as salt and stochastic.