通过总结前人有关干支流直角交汇区水流泥沙运动研究成果，归纳了干支流直角交汇区的分区水流泥沙运动特性，初步探讨了交汇区局部水头损失计算方法，提出了新的包含水深比及回流长度的局部水头损失系数计算公式，采用长江科学院水槽试验成果对计算公式进行了验证。验证结果表明：在汇流比较小时，计算与试验成果吻合较好。

 The motion laws of flow structure and sediment transport in right-angled conjunction area of main and branch channels are complicated which makes the corresponding further researches into predicaments. Through summarizing and analyzing those previous corresponding results on the natures of flow structure and sediment transport in the conjunctions, the division characteristics of flow structure and sediment transport had been generalized. Meanwhile the calculation method of local head loss had been preliminary studied. A new equation for calculating the local head loss coefficient associated with the depth ratio and the length of backwater had been presented. The equation was verified by the experimental flume data of Changjiang River Scientific Research Institute. The verified results indicate that the calculated values agree well with the experiment values where the conjunction ratio is small.