中文摘要：

从2种悬沙垂向分布公式出发,结合对数流速分布公式,导出2种常见垂向平均含沙量计算方法的比值关系表达式。讨论了2种方法的区别与联系：两者不一定相等,比值可以大于1,也可以小于1,当近底相对水深稍大（如大于0.01）时加权平均含沙量小于算术平均含沙量,与实际相符;2种垂向平均含沙量的差异主要由悬沙及流速垂向分布不均匀性引起。对2种方法的实际应用情况进行了初步分析。

英文摘要：

Based on the two formulae for the vertical distribution of suspended sediment and the logarithmic formula for the velocity distribution,the ratio expressions for two common methods to calculate the vertical average sediment concentration were derived.The differences and relations between the two methods were discussed： they were not necessarily equal,and the ratio might be larger or smaller than 1.When the relative depth of near bed was slightly larger（e.g.,larger than 0.01）,the weighted average sediment concentration was less than the arithmetic average sediment concentration,which agreed with the actual situation.The differences between the two vertical average sediment concentrations were mainly caused by the uneven vertical distribution of velocity and suspended sediment.Applications of the two methods were preliminarily analyzed.