Abstract: The mismatch between mining rights and the land-use requirements is a key issue restricting the development of mineral resources. The portfolio supply of mineral and land resource assets provides institutional support for resolving problems such as the separate allocation of rights in mineral resources development. To address issues such as the inadequate identification of synergistic effects and the lack of overall price evaluation methods for “mineral resources + land” portfolio supply, this paper defines the conceptual boundaries of natural resource assets portfolio supply, summarizes and refines four typical modes of natural resource assets portfolio supply, and analyzes the spatial relationships among the components of asset portfolios and the characteristics of their synergistic effects based on national pilot cases. It further clarifies the spatial combination patterns of “mineral resources + land” and identifies three key factors contributing to synergistic effects, namely spatial synergy, industrial linkages, and transaction cost savings. A synergistic effect evaluation model incorporating these driving factors and their interactions is constructed, revealing the value enhancement mechanism of asset portfolios under multi-factor spatial coupling. On this basis, an overall price evaluation method for the portfolio supply of “mineral resources + land” is proposed. The research results provide a reference for the integrated allocation of mineral and land resources and the overall evaluation of asset portfolios.