[Objective] The purpose of this research is to explore the correlation between land use structure and water quality in Shanxi reservoir watershed, and to provide basis for land use development and water source protection in sourthern hilly areas.[Methods] The 23 monitoring sections were set up in the reservoir area and the inflow point of the river. Sampling and monitoring were carried out in July 2017 and January 2018. The land use types of the research area were classified by using the 2016 TM image data. The whole basin was divided into 8 sub-basins by the hydrology and spatial analysis functions of ArcGIS so as to analyze the land use structure of each sub-basin. Four water quality monitoring indexes such as permanganate index(COD_Mn), total nitrogen(TN), total phosphorus(TP) and dissolved oxygen(DO) were selected to analyze their spatial and temporal distribution characteristics and to explore the impact of land use structure on water quality in different slopes of the sub-basin.[Results] The land of Shanxi reservoir is mainly forest, grassland and arable land that accounts for the 80% of total basin area. The water quality of river banks in dry season is better than that in wet season. Each water quality index was negatively correlated with the proportion of forest and grassland, but positively correlated with cultivated land and construction land. The correlation between land use structure and water quality was more obvious in wet season than in dry season. The correlation between water quality and land use types on different slopes was different, COD_Mn in low slope zone(< 15°) was positively correlated with the proportion of cultivated land, TN and TP in middle slope zone(< 15°~25°) were negatively correlated with the proportion of forest and grassland, and TN was positively correlated with the proportion of cultivated land.[Conclusion] Most of the water quality in the reservoir area were good. The forest, grassland and cultivated land are the main land use types affecting the concentration of pollutants in water at watershed scale. Cultivated land is the main source of nitrogen and phosphorus output in wet season. Forest and grassland reduce the nitrogen and phosphorus into the rivers to a certain extent, which has a positive effect.