The invention discloses an indoor test device for simulating dynamic underwater grouting plugging of underground engineering, and belongs to the technical field of seepage prevention and plugging of underground engineering. The device comprises a simulated dynamic water tank, a water inlet and a liquid outlet are formed in the two ends of the water tank respectively, the water inlet controls the water pressure and the flow speed, and a waste liquid collecting barrel is arranged at the water outlet. The device grouting equipment is composed of a liquid inlet, a stirrer and a stirring speed controller. The device for rapidly testing the dispersity resistance of the grouting material provides a rapid and effective judgment means for selection of grout for stopping water and plugging water inpractical engineering. The device is simple in structure, convenient to operate and accurate in test. The gel deposition process and the diffusion distribution rule of the slurry material under the flowing water condition can be intuitively observed, and a simple, convenient, rapid, effective and scientific evaluation method for selecting an appropriate grouting material is provided for treating disasters such as water bursting and mud bursting of underground engineering in engineering practice.