Loess, paleosol and sandy loam make up the major lithologic characters of Quaternary sediments in loessial plateau of northern Shaanxi. As they are not obviously different from each other in conductivity and electrochemical activity, it is quite difficult to distinguish them accurately by means of ap parent resistivity logging curves and spontaneous logging curves. This paper applies such mathematical methods as regression analysis, discriminatory ana lysis and fussy cluster analysis to the lithological division of Quaternary sedi ments in loessial plateau of Northern Shaanxi. The fussy cluster analysis, in particular, shows quite good geological effects in distinguishing loess, paleosol and sandy loam.