Ever since the Miocene time,aeolian dust has been falling down over Northwestern China,forming the Loess Plateau.The dust sedimentations have never been intermitted even in the soilforming periods when the climates were warmer and wetter.The peculiarity of the pedogenic processes of the loess lies in the synchronization of the soil forming processes and sedimentation of aeolian dust,thus making the profile thick and uniform,with complex properties.The parent materials of the paleosols are not the underlying loess,but the aeolian materials,which were accumulated constantly during the soilforming processes.There is not typical buried A horizon in the paleosols.It is not reasonable to classify paleosol profiles into A,B and C horizons.Owing to the continuous input of dust with plenty of carbonate,the pedogenic strength of the paleosols is steadily weakened,and thus has even not yet reached the level of the Brown Soil in most cases in Loess Plateau.