根据对流扩散方程，从数学上定义了洪水波的推移和坦化作用．根据累积量定理，建立了汇流参数与洪水波的波速以及扩散系数之间的关系，并在此基础上，对汇流参数的推移和坦化作用进行了分析和论证．结果表明：在概念性元素方面，线性渠道只反映了洪水波的推移作用，线性水库既反映了洪水波的推移作用，又反映了洪水波的坦化作用；在河道汇流模型中．有些参数单独反映了洪水波的推移或坦化作用，有些参数同时反映了洪水波的推移和坦化作用． According to the convection-diffusion equation, the transition and denial of flood wave are mathematically defined. Based on the cumulant theorem, the relationship between confluence parameters and the wave velocity and diffusion coefficient of flood waves is established. On the basis of this, the transition and denial of confluence parameters are analyzed and demonstrated. The results show that the linear channel only reflects the role of flood waves in the conceptual elements. The linear reservoir reflects both the flood waves and the densification of flood waves. Some parameters reflect the transition or denial of flood waves alone, and some of the parameters reflect the transition and denial of flood waves at the same time.