Abstract: The authors discusses the merits and shortcomings of two means of Delphi value-assigning, and analyzed the principles and procedures of Delphi. In the national mineral resources potential assessment project, experts are invited to assess overall iron and aluminum resource in China province by province. This is the first time that Delphi method was applied in mineral assessment around China. During the execution, three probability values was given: 90%, 50%, 10%, and the experts gave their opinion, then by means of relative software, data will be verified, adjusted, reverified. Resources within three depth range can thus be obtained: within 500 meters, within 1000 meters, and within 2000 meters (not for bauxite). The result of the assessment is regarded to be reasonable and effective, the future of China minerals iron and aluminum is good.