With the increasing emphasis of the state on water conservancy projects, the management model of major water conservancy projects is facing new challenges. Given their huge investment scale, long construction period, and high technical complexity, an effective project management model can ensure project quality, progress, and social benefits. Taking the G River regulation project as a case study, this paper constructs an evaluation index system and objectively assigns weights using the CRITIC method. Secondly, through improved TOPSIS decision-making model, combined with the analysis of the virtual worst solution and grey relational degree, a multi-dimensional evaluation is carried out for eight combination schemes, such as “contract awarding method + owner management method”. The results show that “EPC multi-bid section + whole-process consultation” mode performs better in terms of resource integration efficiency, risk diversification ability, and construction period control. Compared with the traditional “EPC single-bid section + whole-process consultation” mode, it improves the management efficiency, verifying the advantages of the collaboration between multi-bid section contract awarding and whole-process consultation.