In order to systematically reflect the soil erosion characteristics of typical water erosion small watershed in Mollisols region, in this study, NDVI was calculated based on continuous Landsat TM/OLI images. Based on the optimized soil and land use parameters, combined with field surveys, the average soil erosion modulus and erosion deposition distribution pattern in the Guangrong Small Watershed of Helen City from 2000 to 2021 were simulated using the China Soil Loss Equation (CSLE) and the Unit Flow Weighted Erosion Deposition (USPED) model, respectively. Meanwhile, the spatial distribution of snowmelt erosion in spring 2017 was simulated by the snowmelt erosion model (SHI), and the causes of erosion patterns in the small watershed were comprehensively analyzed. The results showed that from 2000 to 2021, the CSLE simulation found that the average soil erosion modulus was 5.57 t/(hm²·a), and the average soil loss was 0.55 mm/a. The erosion on slope was relatively small, belonging to slight erosion[0~2 t/(hm²·a)]. The middle of the slope was in the very strong erosion and strong erosion class, and the erosion contribution was mainly from the slope 2°~6° area, accounting for 79.56% of the total erosion amount. USPED simulation found that 78.11% of the small watershed area was eroded or deposited, of which the erosion area accounted for 24.89% of the watershed area, and the average erosion modulus was 9.40 t/(hm²·a), and most of them concentrated in the erosion gullies at the middle and bottom of the slope. The deposition area accounted for 53.22% of the watershed area, and the average deposition modulus was -4.39 t/(hm²·a). Affected by changes in rainfall, the average erosion modulus of small watershed showed an overall upward trend from 2000 to 2021, with erosive rainfall concentrated in July and August. The results of the SHI model showed that the average erosion modulus of the small watershed was 1.65 t/(hm²·a) in the spring of 2017, accounting for 32.07% of the total erosion in that year, which was higher than the snowmelt erosion modulus calculated based on the snowfall data. The results of the study could provide a scientific basis for simulation and scientific prevention and control of soil erosion in typical Mollisols small watershed in Northeast China.