Abstract: In order to meet the requirements of the grouting materials used in fractured zones and solve the uneasy controlling problem for diffusion distance of the conventional single cement grout, a new cement grout-plastic & early strengthing cement grout-was developed. Through the study on the rheological properties of the plastic & early strengthing cement grout, in combination with a planar fissure diffusion model, the paper discussed that the dynamic shear force, plastic viscosity and its variation characteristics versus time were the essence for the rapid decrease of grouting pressure and small diffusion range in its diffusion process. It is a new type of grouting material which can adapt to hydrogeological features of fault zone.