For exploring the response of water quality of water function area to land use pattern in the Dongjiang River Basin in Guangdong Province, the water quality monitoring data of water function area and Landsat 8 OLI image in 2013 are selected in this study. The water quality monitoring data contains CODMn, NH3-N and TP. The response relationship and correlation coefficient between land use structure in riparian zone and water quality monitoring data are analyzed on different spatial scales by using remote sensing classification, GIS spatial analysis and mathematical analysis methods. The results reveal that water quality is relatively poor in the highly-urbanized area, which is in contrast to the protected areas, reserves and buffer strip. The land use structure of the riparian zone exerts a great impact on water quality parameters in the water function areas. The land use structure of farmland, forest and grassland shows positive effects on water quality. However, the land use structure of water body and construction land has negative effects. CODMn shows a higher correlation with farmland, forest, grassland and construction land than NH3-N and TP. The main sources of the pollutants are industrial wastewater, sewage and atmospheric pollutants subsidence. The increase of urban impervious surface deteriorates the water quality. The cropland and grassland are most relevant to water quality on small riparian zone scale. The correlation coefficient between forest and construction land and water quality increases with the riparian zone scale. The correlation between water body and water quality is significant and fluctuates with the scale of riparian zone.