Every vertex ???? of a graph that is connected has two corresponding vertices ???? and ???? in the vertex subset ???? such that ???? is on some ???? − ???? detour paths in ????. This set ???? is named as a detour set and the detour number of ????, indicated by the symbol ????????(????), is the least cardinality of a detour set. If every subgraph ???????? , 1 ≤ ???? ≤ ???? of ???? has the same detour number as the graph ????, then ???? has a detour selfdecomposition. The detour self-decomposition number of a graph ????, denoted as ????????????????(????), is the highest cardinality of the detour self-decomposition П = (????1, ????2, . . . , ????????) . This decomposition's few bounds and a few general features are investigated here.