Water spraying is widely used in dust reduction of coal mines. A set of dust governance system urgently requires spray effects and its characteristics. A spray distribution characterization system is invented in this study. With CFD calculation results, the spray droplet size and concentration are measured by this characterization system at speed 0.5, 1, 1.5 and 2 m/s in a simulation tunnel. The results demonstrate that the droplet size reaches 5.416 μm through particle collision and evaporation. From 5 m to 30 m, the spray concentration decreases to the fluctuation valley at 15 m and picks up again, whereas the condition varies at the speed of 0.5 m/s. This study provides additional insights for spray characterization and supports the spray dust reduction.