Abstract: According to the complicated mining technical condition，the factors of technology，economy，safety and efficiency are comprehensively considered by using AHP and the gray system theories.The optional gray multilevel decision-making associated model for the under-sea mining method was established，and the weights of the evaluating model were determined by the analytic hierarchy process (AHP).The under-sea mining method by taking the final degree of gray incidence was evaluated.As an example，Sanshandao Gold Mine's practice has proved that the mining method selected by this approach can greatest achieve satisfactory results with safety，high efficiency and low consumption.

Key words: Gray theory, AHP, Mining method, Under-sea mining