In Decision Based Design (DBD) the principal role of a designer is to make decisions. Decision support is crucial to augment this role. In this paper we present a template-based ontological method that integrates the decision making mechanism with problem specific information, thus can provide design decision support from both the “construct” and the “information” perspectives. The “construct”, namely, decision making mechanism, is the utility-based Decision Support Problem (u-sDSP) which is a rigorous mathematical model that facilitates designers making multi-attribute selection decisions under uncertainty. While the information for decision making is archived as u-sDSP templates and represented using frame-based ontology to facilitate reuse, execution and consistency-maintaining. The unique advantage of this ontology is that it captures both the declarative and procedural knowledge of the selection decision and represents them separately, thus facilitates designers reusing, executing previous documented decision knowledge to effect new decisions. The efficacy of ontology is demonstrated using a Rapid Prototyping (RP) resource selection example.