Our major undertaking relates to the modelling of Business Intelligence System (BIS) in term of functionalities for the decision-making process. We regard the BIS as a system that aids in decision-making and dedicated to strategic piloting of a firm. We define BIS as the complex set of Economic Intelligence Process (EI process), principal actors implied (decision maker and watcher) and strategic information system. The EI process on which we are based breaks up into several stages: identification of the decisional problem stake, translation of decisional problem into questions of relevant information search, treatment, analysis and presentation of added value information, interpretation of the relevant indicators to resolve decisional problem, decision, capitalization of strategic knowledge and protection of informational patrimony. The EI process management enables us to identify the criteria of success of this process to ensure its good practice in the firm. We identify strategic factors relating to the clarification of the strategic vision of the decision maker and the realization of a good strategy. A good strategy should be flexible i.e. not only adapted to the scenario in which one believes, but also should allow orientation change if there occurs important events in an environment. The individual factors relate the competence of actors in taking a good decision at the convenient period. The informational factors relate to the evaluation of the information relevance. We also identify organisational factors which translate the flexible nature of the organisational structure allowing the appropriation of BIS, the important degree of decentralization of decision-making and an informational culture which raises a climate of communication favourable to exchange experiences and knowledge. Lastly, the technological factors are summarized in the conception of a knowledge based information system which provides a personalized and adaptive help to the user profile