Exploratory Analysis (EA) is a methodology for complex macroscopical problems under deep uncertainty conditions. Supportive tools are necessary for the successful application of EA. Current EA software is mainly designed for specific applications, and lacks generic and formal modeling capability. A general-purpose EA tool, called EASim, was proposed. EASim uses extended influence diagram as its formal modeling specification. Its functional architecture was discussed firstly. Then the analysis and solutions of several key technologies of EASim were presented. Its software structure, runtime snapshots and technological advantages over Analytica were also presented. EASim has been adopted by several military organizations, verifying its feability.