In this paper the schemes for urban emergency water supply are evaluated and sorted with Gray Target to establish index system of water quantity, water quality, engineering difficulty and investment etc. its steps includes: establishing standard mode, gray target transformation, building gray associated with difference information space, calculating gray relational coefficient and approaching coefficient, at last identifying the extent near Grey Bull’s-eye. The model is simple, efficient and feasible. This method is suitable to deal with the uncertainty in less data, incomplete information.
