The night markets are spring up everywhere in Taiwan. they are kind of mini department stores! To help the vendors choose the suitable postions, reduce the risk and draw them up well. The study suggests an essential reference for the executives for choicing market places and their investment appraisal. The study is done by group decision making and collect the opinions from masters and develop the appraisal essential factors by Delphi and Analytic Hierarchy process (AHP) methods. The results show ”variable of the population statistics”, ”feature of the night markets”, ”convenience”, ”expansibility of the business district” and ”competition”. ”variable of the population statistcs” take 35% of the total weight.