Whereas conventional Decision Support System (DSS) helps individual decision makers, Group Decision Support System (GDSS) is designed to help groups of managers who are jointly responsible for making complex strategic decisions. Up to the present, most of researches in strategic GDSS have focused on the hardware such as email system, electronic meeting system, video conferencing system, etc. On the other hand, it is needed to study on the process of strategic group decisions which assists to structure complex decision problems and resolve uncertain ones. In particular, among the process the pooling mechanisms of individual opinions are required for making the decisions. However, it is not at all done to aggregate the diverse opinions of individuals in GDSS area. This research focuses on two issues in GDSS : the process of strategic group decision making and the aggregation of a number of individual opinions. For the purpose, We first propose a framework of Strategic Decision Making Process (SDMP) in which to be participated multi-persons, i.e., a group. Second, the multi-opinion pooling methods which need to each phase of the process of strategic group decision are presented. Based on the pooling methods, we develop a opinion pooling support system (OPSS) to improve the facility of group decision making. The developed system is illustrated with an example.