Abstract: Blocking water of hydrodynamic roadway by aggregate pouring in water inrush mines is an important method for mine rescue. To study its mechanism, the experimental platform of similar simulation test was established based on such factors as water head height, flow rate, roadway size, inclination angle, roughness, aggregate particle size and perfusion speed. Based on the platform, single-hole and multi-hole pouring tests were carried out to analyze the movement and accumulation law of aggregate in hydrodynamic pathway. The results are as follows. Firstly, the accumulation body has the characteristics of migration and growth to the downstream during the normal pouring period, and the formation mechanism of the slope shape of the upstream and downstream is confirmed. Under the condition of low flow rate, the aggregate will connect to the top in a rapid speed and there are cavities between the holes. Under the condition of high flow rate, the accumulation body between the holes will gradually connect and the pouring volume will be superimposed on each other downstream. Secondly, several typical phenomena are found, including the U-shaped distribution characteristics of the residual water passage, the disturbing flow top effect in the rough roadway, the air erosion effect, the hole plugging effect, and the dam break scouring effect. Thirdly, combined with analytical method and numerical method, the reliability of the test platform is verified from the starting speed of aggregate particles and the key phenomena in the process of aggregate accumulation. Finally, by a slurry grouting test, it is proved that the slurry ratio and the size of aggregate particles have a great influence on the grouting effect, and that the slurry has spatial zoning in the aggregate accumulation. The test platform has a guiding significance for the optimization of water-blocking engineering technology.