Abstract: Splitting grouting is widely used in practical engineering. Due to the many factors influencing the diffusion of slurry, the mechanism of splitting grouting is not clear, especially the researches about effects of different pressure modes (regulation and pulsation) on the diffusion of slurry are scarce. The mechanism of splitting grouting of the above 2 pressure modes is discussed. As for the regulatory grouting, based on the expansion form of splitting cracks to consider the movement of slurry, the diffusion process is described as elliptical planar radiation using hydraulic fracturing model, and the equation for diffusion of splitting grouting under stable-pressure grouting is deduced. The influences of grouting pressure, slurry viscosity, elastic modulus and splitting channel width on diffusion area are analyzed. As for the pulsating grouting, slurry will make the split channel width gradually increase on account of the delay effect of the load applied to the filling and pulsating superposition. The grouting model for oblate ellipsoid is adopted, and the diffusion law of slurry of pulsating grouting is deduced. The results show that there is a minimum on the curve of relationship between the dispersion distance of slurry and the fluctuation frequency, occurring when the frequency is 10 times per minute. The parameter can be used as a control parameter for pulsating grouting. Finally, the difference between the grouting methods is studied by comparing the regulator grouting mode and the pulsation model. The diffusion distance of the latter is far shorter than that of the former. It is shown by using the pulsating grouting and adjusting the parameters can effectively control the diffusion range of slurry. The rules can provide a theoretical basis for engineering practice.