Urban Affairs decision is the key influential element on urban planning. Most of the urban planning in Taiwan is decided with group decision making method which is mainly operated with mediation to integrate committee members' opinions. During the mediation process, the alternatives operative possibility is either not fully analyzed or decided by the majority rule. Such black box decision making about urban affairs cannot operated again and again because that the increased social cost from inappropriate decision will be harmful to the country. Due to the results described above, the most important issue of all is to formulate appropriate urban affairs model with open and objective decision process. The relative reviews demonstrated that Fuzzy Delphi Method and Fuzzy Analytic Hierarchy Process could be used to improve the weakness while applying group decision making method on urban affairs decisions. The traditional decision makers in the past always made decisions according to their own preference and specialization instead of rational analysis. By applying Fuzzy Delphi Method and Fuzzy Analytic Hierarchy Process on urban affairs decisions, the problems from group decision making method can be avoided. It is very important to use the open, fair, and objective decision pattern on urban affairs. The purpose of this paper is to formulate the evaluation model of urban affairs including expertise perception on urban environmental quality analysis as well as weighting measurement of perception factors. Finally, HsinChu area is used as an example to evaluate the urban development patterns among the alternatives of "Urban Smart Growth", "New Urbanism", and "Optimal City Size".