Compared　with　two-level　meta-frontier,　three-level　meta-frontier　can　have　more　projection　direction　to　select.　However,　at　present,　three-level　meta-frontier　framework　mainly　adopts　the　traditional　exogenous　projection,　which　makes　it　continue　the　defects　of　two-level　meta-frontier,　that　is,　in　the　non-radial　data　envelopment　analysis　(DEA)　model,　there　may　be　an　unreasonable　technology　gap　ratio　(TGR),　which　is　not　conducive　to　effectively　evaluating　the　efficiency　of　decision-making　units　(DMUs).　By　decomposing　the　projection　process,　the　combined　projection　method　is　proposed　to　solve　the　above　problems.　In　the　selection　of　projection　direction,　the　selection　methods　of　layer-by-layer　accumulation　projection　(LA)　and　accumulation　consistency　projection　(AC)　are　proposed,　and　thus　some　new　combined　projection　methods　are　established.　In　addition,　the　improvement　of　projection　methods　in　two-level　meta-frontier　are　introduced　into　three-level　meta-frontier,　and　then　different　combined　projection　methods　are　compared.　A　numerical　example　and　an　empirical　application　are　given　to　compare　different　combined　projection　methods,　and　the　results　support　the　use　of　our　proposed　combined　projection　methods.　©　The　Author(s)　under　exclusive　licence　to　Sociedade　Brasileira　de　Matemática　Aplicada　e　Computacional　2024.