[Objective] The effects of different rainfall characteristics and different underlying surface conditions on soil erosion and sediment yield were determined in a low mountain and hilly area of Lianyungang City, Jiangsu Province, in order to provide a reference for local soil and water loss prevention and improvement of soil and water conservation benefits.[Methods] Local erosive rainfall types from the Heilin soil and water conservation monitoring point from 2013 to 2020 were classified by the K-means clustering method. The characteristics of erosive rainfall were identified and the correlations among rainfall, runoff, and sediment yield of five slope runoff plots at the monitoring point were analyzed by the grey correlation method. Differences in runoff and sediment yield capacity due to different underlying surface conditions were compared by the double accumulation curve method, and the soil and water conservation effects of human activities on surface disturbance were analyzed.[Results] ① Erosive rainfall mainly occurred during the flood season, mainly from type Ⅰ (small rainfall and light rainfall intensity) rainfall events, accounting for 66% of the rainfall frequency, followed by type Ⅱ (medium rainfall and medium rainfall intensity) rainfall events and type Ⅳ (large rainfall and medium rainfall intensity) rainfall events. Type Ⅲ (large rainfall and heavy rainfall intensity) rainfall events were the least frequent type of rainfall events; ② Sediment yield was closely related to rainfall and runoff depth, and the correlation coefficient ranges were 0.64~0.85 and 0.61~0.86. respectively; ③ The runoff and sediment yield of secondary rainfall caused by type Ⅲ rainfall were the largest, and the total amount of soil loss caused by type Ⅳ rainfall was the largest; ④ The sediment yield capacity of agricultural land was the largest, followed by forest land. The sediment yield capacity of natural wasteland was the smallest. Reducing the artificial disturbance of surface soil, horizontal ridging and planting, and selecting plants with high coverage were more conducive to improving local soil and water conservation benefits. On the whole, the soil and water conservation benefits of forest land were greater than those of agricultural land. ⑤ The differences in runoff and sediment yield due to different underlying surfaces decreased gradually with increasing rainfall and rainfall intensity.[Conclusion] Erosive rainfall mainly occurred during the flood season in a low mountain and hilly area of Lianyungang City. There were obvious differences in the characteristics of runoff and sediment yield due to different rainfall types and underlying surfaces, and the benefits of forest land to soil and water conservation were greater than those of agricultural land.