As an essential factor of landform,slope gradient has impacted the processes of transformation of materials and energies.The main researches on slope have been reviewed,including slope mapping,slope effects of DEM type,slope scale effects involved to DEM resolutions,and transformation of coarser resolution DEM derived slope.The main problems puzzled researchers on slope is slope mapping methods,in which slope was thought of discrete data and mapping for each of the classes.These methods were not matched to development of GIS and DEM applications,and do not meet the requirements of modeling in watershed hydrology and regional soil erosion as well.Considering the application of slope in hydrology and regional erosion modeling,the vegetation suitability assessing and mapping,main topics to be studied on slope include effects of DEMs from varied interpolation strategies,mechanisms of reduction for coarser resolution DEMs derived slopes,methods and model for coarser slope transformation,and application of scaled slope surface in studies of hydrologic and erosion models at the regional scale.