Abstract: This article based on the measurement and research of several rapids shoal on Lancang river，by the shoal formation flows that we get the preliminary hydraulic index of representative ships． That preliminary hydraulic index is not systematic，and is not conducive to use in project． It needs systematization to get the series index． By force balance analysis on ship effective thrust and navigation resistance，export the reasonable expression of rapids shoal and away flow shoal hydraulic index，merge the flow and slope into a general． Away beach index that called the away beach distinguish number． Using the away beach distinguish number expression to curve fitting the preliminary hydraulic index，which can be simply identified that the systematic away beach hydraulic index is reasonable and easy for use．

Key words: riffle shoal, hydraulic parameter of rapids abating, rapids of flow method, rapid determination coefficients

摘要： 依据澜沧江多个急滩的实测和研究成果，采用成滩流量法获取了代表船型的初步消滩水力指标，指出初步消滩 水力指标存在数据离散、指标不系统、难应用等不足，需要将其推算为常规的便于应用的系列指标; 通过船舶有效推力与航行阻力受力平衡分析，导出急滩消滩水力指标的合理表达式，将流速、比降合并为一个称为消滩判数的综合消滩指标; 用消滩判数表达式对初步消滩水力指标进行曲线拟合，可简单地确定出应用方便的合理的系列消滩水力指标。

关键词: 急滩, 消滩水力指标, 成滩流量法, 消滩判数