To explore the status of net anthropogenic phosphorus input (NAPI) and its influencing factors in the Beijing-Tianjin-Hebei region, this study took 13 prefecture-level cities as research units, collected relevant statistical data and NAPI model parameters from 1990 to 2022, analyzed the spatiotemporal characteristics of NAPI and the variation trends of its components over the 33 years, and used redundancy analysis (RDA) to quantitatively reveal the impacts of different types of factors on NAPI and its components. The results showed that:(1) The overall NAPI in the Beijing-Tianjin-Hebei region showed a fluctuating upward trend, with a significant increase from 1990 to 2006 and a slight decrease from 2006 to 2022. The annual average value was 1906kg/(km²·a), which was 5.6times the national level. Phosphorus input from chemical fertilizers was the most important source, with an average annual contribution rate of 54.90%, followed by phosphorus input from food and feed, with an average annual contribution rate of 41.18%. Affected by terrain, the spatial distribution of NAPI showed a trend of gradually decreasing from south to north. Handan City had the highest NAPI value, accounting for 15.76% of the entire study area, while Chengde City had the lowest NAPI value, accounting for 1.52%. The average uncertainty range of NAPI from 2018 to 2022 was -14.81% to 14.56%. (2) The order of influence of different factors on NAPI and its components was: land use factors > economic factors > social factors, and the combined explanatory rate of the three types of factors was 81.77%. Among them, NAPI and its components were only negatively correlated with the proportion of forest and grassland areas, and positively correlated with other influencing factors. Among the indicators, the proportion of construction land area had the highest individual explanatory rate of 45.70%, and had the strongest positive correlation with food/feed phosphorus and non-food phosphorus, making it the most critical factor affecting NAPI and its components. The increase in the proportion of construction land area is often accompanied by intense human activities, such as the increase in food consumption and detergent use. Therefore, the positive impact of the proportion of construction land on food/feed phosphorus and non-food phosphorus leads to its highest individual explanatory rate.