In order to explore the effects of grinding time and hydration time on the rheological properties of coal gangue-based grouting materials, through systematic experiments, the rheological properties of coal gangue-ordinary silicate composite slurry under different conditions of coal gangue grinding time (particle size distribution), water-cement ratio and hydration time were tested by rotating viscosity instrument. The rheological behavior of coal gangue-based composite slurry under different water-glue ratios was analyzed. It is found that the water-glue ratio is the main factor affecting the flocculation structure of composite gel materials, while the particle size has a relatively small effect on the flocculation structure of the slurry. When the water-glue ratio is 0.6, 0.8 and 1.0, the composite slurry exhibits the Hershel-Bulkley rheological mode with yield stress, and when the water-glue ratio increases to 1.5, the rheological behavior of the slurry changes to Bingham plastic fluid mode, and when the water-glue ratio reaches 2.0, the slurry exhibits Newtonian fluid mode. Further studies show that the grinding time of gangue powder significantly affects the yield stress of the slurry, and the yield stress increases with the extension of grinding time, especially under the condition of low water-glue ratio. In addition, the change of particle size in the Hershel-Bulkley rheological mode did not cause a regular response of consistency coefficient and rheological index at low water-to-glue ratio, indicating that the evolution of flocculation structure in the slurry was not solely regulated by particle size. Through the test of slurry at different mixing times (5, 10, 20, 40, 60 min), it is found that the shear stress of the slurry increases with the increase of hydration time, and the relationship between shear stress and hydration time can be established.