Abstract: The northern coast of the Yellow River Delta has lost its sediment supply from the Yellow River basin and experienced continuous erosion under ocean power since the cut-off of Diaokou River in 1976. The ecological resources of wetland in the Yellow River Delta Northern Nature Reserve (YRDNNR), located at the mouth of the Diaokou River, are thus under threat. The erosion of YRDNNR was evaluated by using spatial analysis technique based on the topography data measured on the north bank of the Yellow River Delta in this paper. The results show that from year 1992 to 2015, continuous erosion occurred in this area, the annual erosion volume reached 2 856×10⁴ t, the annual eroded thickness was 9.3 cm, and the erosion rate remained rather stable. Based on the historical runoff of Lijin hydrological station of the Yellow River, the paper tries to put forward a quantitative scheme to compensate the erosion in the YRDNNR. According to the analysis, during the period of water-sediment modulation, water diversion through Diaokou River at a flow rate of 1 200 m³/s for 19 days can effectively alleviate the erosion of the reserve.