【目的】为广东省北江流域及其邻近地区沉水植物资源的保护提供参考。【方法】采用实地踏查和样方调查法，于2009—2013年调查了广东北江上游的沉水植物群落多样性及其所在水域的水质。【结果】在韶关市浈水(SG1)、北江(SG2)、武江（SG3）和南水（SG4和SG5）等5个调查点，共记录了沉水植物12种，其中包括11种被子植物和1种藻类植物，均为广域分布种；群落以竹叶眼子菜Potamogeton wrightii、黑藻Hydrilla verticillata、密刺苦草Vallisneria denseserrulata和穗状狐尾藻Myriophyllum spicatum为优势种，微齿眼子菜P.maackianus为广东省首次记录。水质检测结果表明，北江流域水质变化较大的指标主要是总氮（TN）、总磷(TP)、氨氮（NH4+-N）含量和化学需氧量（CODCr）。南水2个调查点除TN和NH4+-N外，其余指标达到或接近国家I级质量水平，其余调查点的TN含量和CODCr 处于国家水质标准II~III级。TP、NH4+-N含量和CODCr 以冬季较高，TN含量以夏季较高。【结论】北江流域沉水植物物种丰富度较低，其群落的物种丰富度与所在流域的人为活动密切相关，水质最佳的南水物种丰富度和多样性最高，水质最差的浈江物种丰富度最低。工业污染、水电站大坝建设和挖沙等因素是导致北江流域沉水植物物种多样性下降的主要原因。
【Objective】To provide references for protection of submerged plant resources in Beijiang River valley and surrounding areas, Guangdong.【Method】The species diversity of submerged plant communities and the water quality where these plants grow were investigated from 2009 to 2013 using on-site survey and quadrat survey methods. 【Result】A total of 11 angiosperms and one macro-alga were recorded at five sites, Zhengjiang of Renhua County (SG1), Beijiang of Qujiang District (SG2), Wujiang of Zhengjiang District (SG3), and Nanshui of Ruyuan County (SG4 and SG5). All recorded plants belong to widespread species. The dominant species were Potamogeton wrightii，Hydrilla verticillata，Vallisneria denseserrulata, and Myriophyllum spicatum. It was the first time that P.maackianus was recorded in Guangdong. The water quality test results showed that the major pollutions in Beijiang River valley were TN, TP, NH4+-N and CODCr. Except for TN and NH4+-N, the contents of the other parameters at two sites(SG4, SG5) of Nanshui met or approached the class I level of National Water Quality Standard, and the contents of TN and CODCr at the other sites were between class II and III. The contents of TP, NH4+-N and CODCr were relatively high in winter, while TN contents were relatively high in summer.【Conclusion】The species richness of submerged plants in Beijiang River valley is relatively low. The species diversity of the plant community is closely related to local human activities, with the species richness and diversity being the highest in Nanshui where the water quality is the best, and the lowest in Zhengjiang where the water quality is the worst. Industrial pollution, building of hydropower station dam and sand-excavating are the major factors causing declining of the species diversity of the submerged plants in Beijiang River valley.