In order to scientifically allocate replaced water from east-route and mid-route of the South to North Water Transfer Project, which is allocated initially to downstream regions of yellow river,and again to the upstream and midstream areas, based on analysis on TOPSIS,this paper pointed out the problem that short distance may be coinstantaneous between the scheme to ideal solution and that to opposite ideal solution. “Vertical distance” is proposed to replace Euclid distance, at the same time, TOPSIS model is improved and applied. Through calculating distance between allocation water indexes of upstream and midstream areas of yellow river and ideal solution, the percentage and the amount of allocation water can be gained. The outcome can be used to provide decision basis with allocation water proposed in the paper.And the study result is important to mitigate inconsistency between supply and demand in yellow river watershed.
