Abstract: Ephemeral gullies are small channels formed by surface runoff. Although they can be temporarily eliminated by tillage, they tend to reappear in the same location. Ephemeral gully erosion is one of the main types of soil erosion in cultivated land across the black soil region of Northeast China and poses a serious threat to land productivity and crop quality. To investigate the interannual variation and spatial differences in ephemeral gully erosion and to develop a prediction model. UAV-based surveys were conducted over two consecutive years in the northern part of the typical black soil distribution zone. In the black soil region of Northeast China, ephemeral gullies formed by rainfall runoff generally reach their peak development by the end of the rainy season in late September. Due to the uncertainty of the specific time of autumn harvest across different regions, the influence of crop cover before harvest is significant, and after harvest, ephemeral gullies are disturbed, making UAV-based measurements at a regional scale difficult. However, in early summer, when the rainfall of the year has accumulated to some extent, ephemeral gullies have already redeveloped, and crop cover is still relatively low, making it a more suitable time for UAV-based surveys. Therefore, this study chose to conduct UAV-based surveys from June 28 to July 29 in 2022 and from June 8 to July 1 in 2023. The surveys covered all sample units in Bin County, Bayan County, Baiquan County, Hailun City, Mingshui County, Keshan County, and Nenjiang City, acquiring DSM and imagery with an accuracy of approximately 3.8 cm to capture the morphological characteristics of ephemeral gullies and their influencing factors. The results showed that: 1) Ephemeral gully erosion intensity exhibited significant interannual variation influenced by rainfall differences. Among 66 survey units, the proportion of units with observed ephemeral gullies was 75.78% in 2022 and 74.24% in 2023. In 2023, the average liner density, areal density, and volumetric density of ephemeral gullies decreased by 31.67%, 36.72%, and 40.78%, respectively, mainly due to lower rainfall during the same period. 2) In 2022, 215 ephemeral gullies were identified in 50 survey units, while in 2023, 151 gullies were found in 49 units, totaling 366 gullies over the two years. The average gully length, area, and volume were 99.26 m, 232.92 m², and 35.76 m³, respectively. In 2023, the number of gullies was only 70% of that in 2022, and the average length, area, and volume decreased by 16.06%, 23.55%, and 28.06%, respectively. 3) In 2022, 46 ephemeral gullies with complete catchment areas were identified, and 27 reappeared in the same locations in 2023. Whether a gully reformed was significantly influenced by differences in catchment area and runoff volume (p < 0.05). Based on these 73 gullies, ephemeral gully development was found to be significantly affected by catchment area and runoff volume. The length, area, and volume of gullies exhibited significant power-law relationships with average catchment slope (S) and runoff (Q), leading to the development of prediction models (n = 73, p < 0.05): L=1.050S^-0.402Q^0.424 （R²=0.548）; A=0.086S^-0.888Q^0.652 （R²=0.606）; V=0.009S^-0.806Q^0.720 （R²=0.546）. These findings provide a valuable reference for the control of ephemeral gully erosion and the development of regional-scale gully prediction models.