The implementation of the "grain-for-green" project has effectively mitigated soil erosion of hill slope on the Loess Plateau. However, gravity erosion, including both shallow landslide and collapse, is widely distributed on the Loess Plateau and has become one of the dominant source of erosion sediment in small watershed. To explore the morphological characteristics and critical topography of shallow landslide and collapse in hilly and gully region of the Loess Plateau, 53 shallow landslides and 40 collapses were investigated in Zhifanggou small watershed in Ansai District, Shaanxi Province, and their vegetation characteristics were also recorded. Photogrammetry was performed by unmanaged aircraft vehicle. The results showed that the sizes of shallow landslide were usually larger than those of collapse. The variations in morphological characteristics of shallow landslide were greater than those of collapse. The length, width, perimeter and area of shallow landslide were negatively correlated with gully density (P<0.01), and were positively correlated with the distance to gully system (P<0.01). Nevertheless, the correlations between the morphological characteristics of collapse, and gully density and distance were loose. Shallow landslide and collapse were concentrated on where the slope and topographic wetness index (30°~55° and 0.50~2.00) were moderate, flow path gradient and flow path length were small (60.0%~120.0% and 0~15.00 m). Nevertheless, in areas where the slope and flow path gradient were large (>55° and >120.0%), and the topographic wetness index and flow path length were small (<0.50 and <15.00 m), gravity erosion was dominated by collapse. On the contrary, in areas where the slope and flow path gradient were small (<30° and <120.0%), and the topographic wetness index and flow path length were large (>2.00 and >15.00 m), gravity erosion was dominated by shallow landslide. Shallow landslide and collapse widely occurred on slopes covered by shrub communities with the aspect of 0~180°. Shallow landslide was also distributed on slopes covered by herbs with the aspects of 0~90° and 270°~360°. The research results are helpful for understanding the occurrence process and critical topographic conditions of shallow landslide and collapse estimating sediment yield and controlling erosion in small watershed.