The author describes the founction of the cut-off wall for underground fill-ing and its development situation, and makes an emphatical introduction to the structural form of flexural filtering cut-off wall with light-duty steel-wire mesh developed recently in China, the force calculation and the constructing steps. In comparison of flexural cut-off wall with wood cut-off wall,the advantage of flexural cut-off wall and its futural applica-tion in the underground mining are confirmed.