An　objective　of　this　paper　is　to　investigate　the　boundary　value　problem　of　a　high-order　nonlinear　fractional　q-difference　equation.　It　was　to　obtain　a　unique　iterative　solution　for　this　problem　by　means　of　applying　a　novel　fixed-point　theorem　of　ψ−　(h,　r)　-concave　operator,　in　which　the　operator　is　increasing　and　defined　in　ordered　sets.　Moreover,　we　construct　a　monotone　explicit　iterative　scheme　to　approximate　the　unique　solution.　Finally,　we　give　an　example　to　illustrate　the　use　of　the　main　result.　©　2023,　The　Author(s).