Abstract: Abstract: As one of the main forms of soil erosion on the hilly Loess Plateau, gully erosion threatens the land resources and causes serious environmental problems. Although different approaches have been used to monitor and predict gully erosion over the years, gully erosion measurement on middle and large scale is still difficult. The objective of this study was to assess the accuracy of measuring gully morphological parameters using stereoscopic satellite images with very high resolution on the hilly Loess Plateau and feasibility of stereoscopic satellite images acting a reliable data source for large scale gully erosion monitoring. GeoEye-1 stereoscopic satellite images (0.5 m panchromatic and 2.0 m multispectral images, acquired in March, 2016) were used to calculate gully morphological parameters of 21 gullies in a catchment located in central Loess Plateau and then test their accuracy by comparing them with 3D (three-dimensional) laser scanning data (0.15 m resolution, acquired in July, 2016), and mean error, percent error and root mean squared error were used for error measure. The results were as follows: 1) The average errors of linear and areal gully parameters, including area, perimeter, length and width, were 3.58 m2, 0.55 m, 0.13 m and -0.10 m, respectively, and the percentage errors were 0.11%-33.81%, 0.41%-18.58%, 0.10%-12.28%, and 0.09%-37.41%, with the average percentage error of 8.96%, 4.83%, 2.92%, and 10.81%, respectively. The percentage errors of area, perimeter, and length were mainly below 5%, and the percentage errors of gully width were mainly below 10%. Overall, the errors of linear and areal gully parameters extracted from high resolution stereoscopic satellite images can be controlled in a lower level. 2) The average errors of 3D gully parameters, including gully bottom width, maximum gully depth, average gully depth, cross sectional area and gully volume, were -0.67 m, 0.14 m, -0.46 m, -6.30 m2 and -54.01 m3, respectively. The percentage errors of 3D gully parameters were 0.39%-84.65%, 0.51%-55.91%, 0-59.64%, 0.13%-81.53%, and 1.98%-88.72%, respectively, with the average percentage error of 30.37%, 24.13%, 27.16%, 37.96% and 37.46%, respectively. The percentage errors of 3D gully parameters were mainly below 50% except the maximum gully depth which was mainly below 30%. Compared with 3D laser scanning, gully bottoms morphology measured with stereoscopic satellite images presented smaller gully depths, gully bottom width and cross sectional area. 3) 3D gully parameters including gully volume, cross sectional area and gully bottom width were correlated significantly with gully scale at the level of 0.05. The larger the scale of the gullies, the smaller the measured gully volume, cross sectional area and gully bottom width from stereoscopic satellite images than 3D laser scanning measurement. A linear regression model was built between measurement errors and gully volumes, which can be used when other measurement approaches are not available. On the whole, the accuracy of measured gully parameters from stereoscopic satellite images will be affected by many factors, such as the resolution of stereoscopic satellite images, the correction accuracy and the number of control points, but it also can provide reliable data for linear and areal gully parameters measurement and new method for 3D parameters measurement of large scale gullies on the hilly Loess Plateau.