Abstract: For exploring the impact of damming and water-storing on spatial distribution of nutrients in the upper and middle reaches of the Heihe River, the spatial heterogeneity of nitrogen and phosphorus nutrients in water samples and sediments collected from 28 different sampling sites from July to August in 2018 and 2019 was determined and analyzed. The results show that the content of nitrogen and phosphorus basically met the class Ⅲ of water quality standard. Nitrogen in water mainly existed in the form of ammonia nitrogen (NH₃-N), while in sediments mostly in the form of nitrate nitrogen (NO₃-N) at the upper and middle reaches of Heihe River. From the perspective of distribution characteristics, the contents of total phosphorus (TP) and total nitrogen (TN) in sediment were the highest in the upstream dammed river. Water temperature (WT), salinity (SAL) and dissolved oxygen (DO) are the key environmental factors affecting the distribution of nitrogen and phosphorus; For the middle reaches, TP and TN contents are the second in natural river reach, and chemical oxygen demand (COD), water temperature and pH are the key environmental factors affecting the distribution of nitrogen and phosphorus. Livestock breeding, mineral mining, industrial and agricultural wastewater discharge are the main sources of nitrogen and phosphorus nutrients in the Heihe River water. The retention effect of dam construction and the changes in environmental factors are main reasons for the uneven spatial distribution of nitrogen and phosphorus. Therefore, the key to improve the health condition of Heihe River is to control the exogenous pollution sources caused by human activities and implement a reasonable reservoir operation mode according to the changing characteristics of different types of pollutants.