In order to analyze the relationship between the configuration characteristics, variable mass permeability characteristics and the catastrophe mechanism of falling column process, The influence of the permeability was studied by diffraction instrument, And using the seepage test system of the fall column, The seepage instability process of variable mass broken rock mass is analyzed, The findings suggest that, The proportion of coarse particles accounted for 89.86%, Fine particles accounted for 10.14%, Broken rock particles is better, Low compression performance; The fall column, under strong hydrodynamic conditions, Due to its strong characteristics of migration and loss with water flow, It is easy to induce the subsidence column protrusion water disaster; As the ratio between coarse and fine aggregates increases, Porosity and permeability are both increased; When the axial displacement does not change, With the increasing circumference pressure, The permeability of the broken rock samples is decreasing; The fitting of the seepage velocity of the broken rock mass to the pore pressure gradient follows the Forchheimer relationship, The seepage of the broken rock mass belongs to the category of non-Darcy flow under the triaxial stress; The instability of the subsidence column fracture rock mass presents three seepage instability forms: initial seepage stage, seepage mutation stage and piping stage in different stages.