The reinforcement effect of grouting is different with different degrees of brokenness of rock mass, as this phenomenon is closely related to the groutability and reconstructability of the broken rock mass. In order to obtain the groutability and reconstructability of mudstones with different degrees of brokenness and their relationship, a permeability device was developed and used to test the permeability of broken mudstones with different particle sizes during the axial compaction process. A computed tomography (CT) scan, uniaxial compression, and non-contact full-field real-time measurement system VIC-3D tests were carried out on the grouted bodies of broken mudstone with different particle sizes. The results show that with the increase of the particle size (i.e., a decrease of the degree of brokenness), the porosity and crack opening formed by the accumulation of broken mudstone increase, so that its groutability will increase, while the volume defect ratio in the grouted body increases first and then decreases, so that its reconstructability decreases first and then increases. During uniaxial compression, the rock-rock contact and weak rock-cement interface in the grouted body are the initial locations of its re-failure, and the grouted body obtained by small particle size is mainly longitudinal splitting failure, while the grouted body obtained by large particles size is mainly shear failure. These above conclusions can provide an experimental data reference and valuable information for predicting and evaluating the groutability and reconstructability of the broken rock mass.