中文摘要：

结合遥感影像、野外调查和水沙数据,以冲积大河为研究对象,分析中国大河的河型分布及成 因.中国大河的冲积河段以弯曲与辫状河型为主,局部河段为分汊与网状河型.综合考虑河型分 布的-般性和特殊性,认为相对输沙率（来沙量与输沙能力之比）、相对河岸侵蚀切应力（近岸水流 切应力与河岸临界抗冲切应力之比）和河谷地形控制（如节点和宽度）是决定河型成因的3个最主 要的因素.

英文摘要：

The distribution of patterns of large alluvial rivers in China and the reason for their formation ＂were analyzed based on remote sensing images, field survey data,hydrological data,and sediment data. Alluvial reaches of rivers in China are mainly meandering and braided reaches,while some local reaches are anabranching and anastomosing reaches. With the general and special characteristics of the distribution of river patterns taken into account,three critical factors are considered to be the main reasons for the formation of river patterns; the relative sediment transport rate （the ratio of the incoming sediment load to the sediment transport capacity）,the relative riverbank erosion shear stress （the ratio of near-bank flow shear stress to the critical erosion-resistant shear stress of the river bank）,and control of valley terrain （e. g., the valley node and channel width） .