Water inrush is a major threat for the coal mining safety in China. The study of mechanical and seepage characteristics of rock mass under stress-radial seepage coupling effect is an important approach to exploring the formation of water-conducting pathway and the mechanism of water inrush disaster in coal mines. In this study, the radial seepage characteristics in the water inrush process were summarized first, and the radial erosion seepage tests of surrounding rock were carried out. Then, the radial water-rock-sand three-phase flow model was established to simulate the water-sediment inrush disasters in coal mines. After this, the creep-erosion coupling properties of weakly-cemented rock mass in coal mining was analyzed by the laboratory test. Finally, the radial seepage disaster mechanism of the surrounding rock was revealed. The main innovations and results are as follows: (1) The erosion seepage was divided into four stages: rapid growth, decelerated growth, slow growth and stable seepage, and the temporal-spatial evolution of the porosity of the surrounding rock was obtained. (2) By numerical simulation, the temporal-spatial evolution of the radial water-rock-sand three-phase flow characteristics (e.g., porosity, rock particle concentration, sand particle concentration, flow velocity, permeability and water pressure, etc.) was obtained. (3) By designing a novel creep-erosion coupling tests system, the synchronous loading of axial compression and radial erosion was realized. And the influence law of different factors on the water inrush characteristics was analyzed based on the creep-erosion coupling test results. (4) A permeability catastrophe characterization model of surrounding rock was established and verified, and the permeability rapid increase stage was regarded as the critical stage in water inrush disaster control.