[Objective]The ecological environment of Qinghai Province is ecologically sensitive and fragile, and it sustains the water ecological security of both China and Asia. Therefore, precisely characterizing the agricultural non-point source pollution load in Qinghai Province is crucial for ensuring regional ecological security. [Methods]Based on statistical data from Qinghai Province for the period 2009-2023, the emissions of total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), and ammonia nitrogen (NH3-N) from crop farming, livestock and poultry breeding, and rural domestic sources were estimated using the emission-factor method. Uncertain parameters were selected for sensitivity analysis, and the contributions of different pollution sources and pollutants were evaluated using the standardized pollution load method. [Results]From 2009 to 2023, the total agricultural non-point source pollution emissions in Qinghai Province showed an increasing trend, rising from 217,288.26 t to 364,869.09 t, an increase of 67.92%. In terms of pollutant type, COD emissions were the largest, ranging from 190,603.48 t to 334,318.81 t and accounting for 87.72%~91.63% of total emissions, followed by TN with emissions of 22,343.76 t to 25,212.20 t, which accounted for 6.91% to 10.28%. Regarding pollution source structure, livestock and poultry breeding was the primary emission source, with emissions of 174,288.15 t~324,337.15 t, contributing 80.21%~88.89% of total emissions. Rural domestic sources ranked second, emitting 27,794.01 t~29,531.32 t and accounting for 7.71%~12.79%. Sensitivity analysis indicated that livestock and poultry breeding was the most sensitive to regional pollution load regulation, identifying it as the priority for control. The total annual standardized pollution load ranged from 44.152 billion m3 to 56.910 billion m3. Among these, TN had the largest standardized load of 22.344 billion to 25.212 billion cubic meters, accounting for 44.30% to 50.61%, making it the primary pollutant. Livestock and poultry breeding had the largest standardized load of 27.236 billion to 43.127 billion cubic meters, accounting for 61.69% to 75.78%, identifying it as the dominant pollution source. From the perspective of the equivalent standard pollution load characteristics, TN from livestock and poultry breeding constituted the largest portion of the standardized load at 11.702 billion to 16.767 billion cubic meters, representing 26.29%~29.46% of the total. [Conclusion]Therefore, addressing agricultural non-point source pollution in Qinghai Province should prioritize the control of livestock and poultry breeding, with TN、COD identified as the key pollutant to control, in order to effectively reduce the regional agricultural pollution load and safeguard the ecological security of the plateau water system.