Rapid socio-economic development related to population growth, food production, and waste management has led to the increasing river export nutrient inputs to the Baiyangdian Lake (BYD), causing severely anthropogenic lake eutrophication. Look ahead, these human-induced nutrient inputs will continue to increase due to the construction of Xiong'an new area. It is thus crucial to provide information on future trends of nutrient loading and its implications for lake restoration. Here we quantified nutrient loadings to the BYD Lake in the different periods during 1995-2015 and assessed their future trends (2050) under changes in land use, agricultural management, and sewage systems. The results showed that multi-year averaged total nitrogen and total phosphorus loadings to the BYD Lake were 2018 ton year^-1 and 313 ton year^-1, respectively. Cropland and directly discharged animal manure were the main sources of total nitrogen and total phosphorus loads, respectively. In terms of land-use change, the growth rates of total nitrogen and total phosphorus loads to the BYD Lake were the highest in 2050 under the scenario of the rapid growth of construction land, increasing by 56% and 60% compared with the baseline scenario in 2010, respectively. The increases are driven by the increasing demands of animal production and wastewater discharge from the growing urban population. As for agricultural management, reducing synthetic fertilizer application was conducive to reducing total nitrogen loadings to the BYD Lake, while controlling directly discharged of animal manure was more helpful for reducing total phosphorus loadings. In 2050, wastewater will become the dominant sources of both total nitrogen and total phosphorus loadings to the BYD Lake. Hence, improving the collection rate and removal efficiency of sewage systems, especially in rural areas, should be put more efforts for the formulation of effective policies for improving the water quality of the BYD Lake. The critical nutrient loads were estimated by the load-response curves from the PCLake model. Knowing the difference between future nutrient loadings and critical nutrient loads is important for lake restoration. The results indicated that reducing the total phosphorus loadings is the key to restore water quality for the BYD Lake. The critical total phosphorus loadings for the III level and IV level of water quality standard are 2.1 mg P m^-2 d^-1 and 2.6 mg P m^-2 d^-1, respectively. To meet the III and IV level of water quality standard, the total phosphorus loadings to the BYD Lake need to be reduced 67 and 131 tons in the scenario of rapid growth of construction land, respectively.