Abstract: Generally, the X-ray diffraction line profile is asymmetrical. A method for fitting the asymmetric diffraction line profile and separating the asymmetric Κα doublet is presented in this paper. According to the diffraction line profile fitting experiments for various functions, a method of a weighted Gauss-Oauchy combination function for asymmetric X-ray diffraction line profile is suggested. It has been proved by practical calculations that when the asymmetric profile function is employedin fitting practical diffraction line, the method is simple and convenient with sati-sfaetorily precise results.