The uncertainty in air attack is one of the important factors interfering with the disposition of area air-defense operation, and every situation of air attack corresponds with one optimum disposition scheme. In order to synthesize the optimum schemes under conditions of every air-combat, this paper transforms the uncertainty of air attack into a multi-object decision problem by analysis, proposes the superiority and E-V criterion, and a method of optimum selection for disposition schemes based on risk decision. The result indicates that the method is simple in model designis, for calculating, and suitable for quick decision-making in disposing troops for battle.