In this paper,a value analysis method that approximates the Gauss distributed and Gauss correlated one dimension random rough surfaces to the random distributed blazed gratings is given.By the statistic simulating analysis of the RMS (root mean square) roughness,the function of the height probability distribution and the function of the auto correlation,the reliability of this method is examined.The potentiality of this method for the solving of the scattering field distribution on the very rough and very undulated random rough surfaces is stated.