海河流域人口密集，工业发达，众多污染源分布在河流附近，大量污染物直接排入河流并最终进入沉积物中，沉积物粒度分布与其中所含污染物的浓度有直接相关关系。同时流域内修建的众多闸坝阻断了河流水沙迁移过程，改变了沉积物的组成分布。因而沉积物的粒度参数空间分布规律的分析对于河流沉积物污染研究及河道的生态恢复具有一定的借鉴意义。本文以海河流域为研究区，应用指标层次+类目综合编码方法对流域内河流进行分类，并采集了漳卫河、徒骇马颊河、子牙河、黑龙港运东、大清河、永定河、北三河、滦河等8个水系的表层沉积物样品，共303个样点。实验室采用激光粒度仪对样品粒度进行测定，得到的参数包括平均粒径、分选系数、偏度系数、峰度系数、粒度频率曲线等。根据Folk and Ward粒度参数分级方法对沉积物粒度参数进行评价。统计沉积物中砂、粉砂与粘土的百分含量，应用Shepard沉积物三角组分图对沉积物类别进行划分。分析了8大水系沉积物粒度参数空间分布规律，并进行相互比较，同时研究了海河流域粒度参数空间分布的南北差异与地形差异（山区与平原），最后以滦河水系为案例，研究了大中型水库对河流沉积物粒度的影响作用。主要结论如下：（1）海河流域8大水系沉积物平均粒径变化范围在19.27~922.8μm，根据平均粒径大小，可将8大水系划分为三类，第一类为大清河、永定河与滦河三个水系，第二类为漳卫河、子牙河与北三河三个水系，第三类是徒骇马颊河与黑龙港运东水系，各水系沉积物粒度大小顺序为大清河>永定河>滦河>漳卫河>子牙河>北三河>黑龙港运东>徒骇马颊河。（2）海河流域八大水系沉积物中粘土含量很低在0~8.55%之间，粉砂和砂为优势组分。Shepard三角图分类结果表明，第一类水系砂、粉砂质砂、砂质粉砂、粉砂沉积物较均匀分布，第二类水系沉积物主要有粉砂质砂、砂质粉砂和粉砂、第三类水系沉积物主要为砂质粉砂和粉砂。（3）海河流域八大水系沉积物整体分选较差，分选状况好坏排序是滦河>北三河>永定河>徒骇马颊河>黑龙港运东>大清河>漳卫河>子牙河。偏度整体呈正偏或极正偏。平原水系黑龙港运东与徒骇马颊河峰态集中在正态与尖锐区间，其他水系另外在平坦区间也有分布。除滦河外，由南到北水系4,5峰沉积物比例有增大趋势而1~3峰减少。（4）海河流域山区水系与平原水系粒度分布比较结果表明，除滦河外，山区水系沉积物平均粒径要显著大于平原水系，从山区到平原，水系沉积物中1~3峰比例减小，而4~5峰比例增大。（5）分别对山区组水系与平原组水系沉积物粒度参数南北空间分布差异进行分析，结果表明北部的滦河山区、永定河山区、大清河山区水系平均粒径较大值要大于南部的漳卫河山区及子牙河山区水系，北部山区水系沉积物分选性好于南部。平原组水系中，北部的大清河、北三河、滦河水系沉积物平均粒径较大值要大于徒骇马颊河、黑龙港运东及漳卫河平原水系，北部平原水系沉积物分选性好于南部平原水系。（6）滦河干流沉积物平均粒径分布规律是在上游波动增大，中游逐渐减小，下游显著增大，而干流各样点海拔高度沿河呈线性下降趋势，地形条件不是关键影响因素。对上游支流上庙宫水库、中下游潘家口与大黑汀、下游支流桃林口水库坝上坝下沉积物粒径比较分析得出，水库对下游河道沉积物有粗化作用，且随水库规模增大，差别越显著。由此得出滦河水系沉积物粒度特殊的空间分布规律是由水系上分布的众多水库的干扰作用形成的。

Haihe River Basin has a large population and numerous industrial towns with most of them locating around rivers. A great deal of pollutions had been discharged into river water and then aggregated in surface sediment. Grain size distribution of sediment has a connection with the concentration of pollutions in it. On the other side, a large amount of dams within the river basin have an impact on the migration of water and sand and hence alter the composition of sediment of the channel. Therefore, the spatial variation in grain size offers a reference for researching on the contaminants inside the sediment and riverbed’s ecological restoration. This article classified rivers within the Haihe River Basin using a multi-index method. 303 surficial sediment samples were collected within eight drainage systems. The grain size parameters were determined by a laser particle analyzer (Microtrac s3500) including Mz, Sorting coefficient, Skewness, Kurtosis and grain size frequency distribution curve. According to the Folk and Ward classification criterion, we determined the level each parameter belonged to. The Shepard ternary diagram was also applied to sort the types of sediments. The spatial distributional characteristics in grain size of sediments of eight drainage systems were contrasted with each other. And we analyzed the discrepancy of grain size distribution between the southern part and the northern and among different landforms. At last, we selected the Luanhe River System as a case to study the influence of large dams on the grain size of sediment downstream. The main conclusions are as follows:(1) The range of Mz within eight water systems is from 19.27 to 922.8μm. Accordingly, these water systems were divided into 3 types. The coarsest one includes Daqinghe, Yongdinghe and Luanhe. The medium one contains Zhangweihe, Ziyahe and Beisanhe. Tuhaimajiahe and Heilonggangyundong are the finest one. The order from coarse to fine is Daqinghe>Yongdinghe>Luanhe>Zhangweihe>Ziyahe>Beisanhe>Heilonggangyundong>Tuhaimajiahe.(2) The proportion of clay is very low within the whole River Basin and it ranged from 0 to 8.55%. The silt and sand components are predominant. According to Shepard ternary diagram, the coarsest sediments consist of sand, silty sand, sandy silt, and silt. The medium consist of silty sand, sandy silt, and silt. The finest contain sandy silt and silt.(3) The samples of eight water systems are poorly sorted. The order from well sorted to poorly sorted is Luanhe> Beisanhe> Yongdinghe> Tuhaimajiahe> Heilonggangyundong> Daqinghe> Zhangweihe> Ziyahe. The sediments are all coarse skewed or very coarse skewed. Sediments from Tuhaimajiahe and Heilonggangyundong which locate on the plain are mesokurtic or leptokurtic. The rest contain platykurtic samples besides the above two types of kurtosis. The multimodal sediment samples (4~5) increase from the southern part to the northern except the Luanhe.(4) From mountain area to the plain within the Haihe River Basin, the Mz of surficial sediments except the Luanhe river system are decreasing distinctly and the proportion of multimodal (4~5) sediments are increasing. (5) The discrepancy analysis of grain size between the north and the south in the mountains and on the plain respectively indicates Mz of Luanhe, Yongdinghe and Daqinghe are higher than Zhangweihe and Ziyahe in mountains. The samples from the northern part are better sorted. On the plain, Mz of Daqinghe, Beisanhe and Luanhe is higher than Tuhaimajiahe, Heilonggangyundong and Zhangweihe. The samples from the northern part are better sorted than the rest.(6) The Mz of Luanhe River sediments is first rising with fluctuations upstream and then decreasing midstream. Grain size in the lower reach becomes very large. Whereas, the altitude of sample is declining linearly. So the landform are not the key factor. By studying grain size variation between upstream and downstream of the dams including Miaogong, Panjiakou and Daheiting and Taolinkou, we got the conclusion that dams lead to the rising of Mz downstream and the degree of Mz discrepancy is enlarging as the size of dam rising. So dams on the Luanhe River Basin are influence factors resulting in the special spatial distribution of grain size.