We present a series of experimental tests on chemical grouting into a fracture with flowing and static water, using a transparent fracture grouting experimental device. Variations of seepage pressure and grout propagation were compared in our investigation. The results show that flowing water results in drops of seepage pressure, development of penetration radii in the upstream side and drops of propagation area during the same period, compared with grouting in static water. The propagation area in static water is always round before grouts reach the joint boundaries. However, the propagation shape changes from round to an elliptic shape for grouting into a fracture with flowing water. A theoretical model for the grout penetration radius in a fracture considering flowing velocity was developed and validated by our experimental results. These results are helpful in improving understanding of fracture grouting mechanism and in guiding engineering practices.