Abstract: Structural surfaces are generally developed widely in the loess slope,can not only alter the continuity of the soil,but also present a significant influence on the seepage,deformation,and stress fields,as well as the stability of the loess slope. In this study,the developmental characteristics and effects of structure surface of loess slope in southern Jing-Yang loess plateau were researched systematically through field investigations,experiments,and numerical simulations. The main results are presented as follows:(1)Considering the difference of formation and influence,the structural surface of the loess slope is classified from the perspective of macro,micro and micro multi-scales into 5 classes and 2 groups and 25 categories. (2)According to the results of the field investigation,the structural surfaces are mostly distributed near the slope shoulder,the orientation of the structural surface is generally in accordance with that of the loess slope. And the length,width,and displacement of the structural surface generally increase with the increase of distance from the slope shoulder. (3)The numerical simulation results show that the development characteristics and influence of the structural surface are various with the change of depth and location. The surface that is near the shoulder and shows large depth is easy to develop. The FOS of the loess slope decreases first and then increases to reach a stable value,with the increase of the distance of the surface from the shoulder. In addition,the FOS gradually decreases to reach a certain value with the increase of surface depth. The results of the paper can provide some basis for the stability evaluation of loess slopes.