The implementation of investment projects in Russia is associated with a lot of different problems caused by non-financial factors. The high degree of uncertainty of the investment situation, the lack of awareness and subjectivity of the decision-makers on the investment choice, the unreasonableness of the selection criteria, as well as the difficulties in the interaction of actors are due to the lack of systematic mechanisms for managing the investment process in the Russian economy as a whole. Together, they form a fairly voluminous complex of related problems. The article is devoted to the study of these problems and ways to solve them. It focuses on the mutual influence of the organization of interaction between participants in the investment process and investment choice procedures. Purpose: to develop proposals for the formation of mechanisms for interaction between stakeholders to ensure a systematic justification of the investment choice. Methods: in the preparation of this article, the methodology of applied system analysis and modeling is implemented, decision-making methods are used, including the Analytical Hierarchy Process. Results: the importance of the pre-investment stage of the investment process as the stage that generates most of the problems of stakeholders is argued. The approach to building system mechanisms of interaction of participants of the investment process at the pre-investment stage is justified. The schemes of such interaction and procedures for making investment decisions are proposed within the framework of the constructed modified model of multi-criteria investment choice. The formation of systemic mechanisms of interaction between participants in the investment process is carried out based on the need for a systematic justification of the multi-criteria choice of an investment project, taking into account the interests of all interested parties. The proposed methodology was developed through the development and modification of the Analytical Hierarchy Process by T. Saati and is aimed at improving the organization of the investment process and the implementation of investment choice based on generalized criteria of satisfaction, efficiency and effectiveness. Сonclusions and Relevance: the formation of system mechanisms of interaction of participants in the investment process at the pre-investment stage was carried out by developing a set of procedures that accompany the process of justifying a multi-criteria investment choice to achieve satisfaction, efficiency and effectiveness of the activities of all actors. The formation of system mechanisms of interaction of participants in the investment process allows to coordinate their interests, opportunities and limitations of the participants' activities, as well as to give the investment process purposefulness and manageability.