Abstract: The total nitrogen, nitrate nitrogen, ammonia nitrogen, and nitrite nitrogen in the upstream reservoir water were determined by the spectrophotometry. The contents of total nitrogen, nitrate nitrogen, ammonia nitrogen, and nitrite nitrogen in the samples collected from the fixed monitoring point of the upstream reservoir in recent two years were determined using the ultraviolet spectrophotometry. The test results were analyzed and compared, and the relationships among the total nitrogen, nitrate nitrogen, ammonia nitrogen, and nitrite nitrogen in the upstream reservoir water were discussed, thus a certain reference for the data analysis and comprehensive evaluation of water quality data in upstream reservoirs is provided.