Most focuses of studies on the ATS for military airplane are how to achieve the ATE and TPS now, but not the total demand of the airplane. Rooted in the bi-level maintenance, the analysis and confirmation of the UUTs on the ATS for military airplane are studied in this paper. The Processes of the analysis and confirmation are divided into two steps that contain preliminary filtration and profound confirmation. Factors that should be focused in the two steps are proposed in the paper.