Abstract: Although the pulsating grouting technology has been widely used, the diffusion mechanism of grout under fluctuating pressure is far behind the engineering practice. For the further promotion and perfection of the pulsation grouting technology, considering the uncertainties of the formation parameters, a permeable diffusion model for power-law fluid under pulsating pressure is established on the basis that the flow rate keeps constant in the sustained segment and zero in the interval segment. Also, the interval distribution equation for the diffusion radius of power-law fluid under pulsating pressure is obtained. Then, by using the designed pulsating seepage grouting simulation test devices, the distribution of power-law fluid in soil strata under different construction parameters is obtained. In numerical process, by constructing the pressure pulsation cycle model and pore rate random distribution model, the simulation of the diffusion process of grout under pulsating pressure infiltration of power-law fluid is also realized. The results show that the diffusion radius of power-law fluid under the pulsation pressure in the soil strata is not a definite value, but concentrated in a certain range with obvious upper and lower bounds, which is impacted significantly by the pulsating grouting pressure and pulsation frequency. With the increase of grouting pressure, the difference between the upper and lower bounds increases, and the dispersion degree appeares more obvious. Besides, the diffusion radii of grout obtained from theoretical calculation, numerical simulation and model tests show the same trend with the change of grouting pressure, and the calculated values from both theory and numerical simulation are acceptable compared to those of model tests. In general, the theoretical formula and the numerical model can describe the diffusion process and the interval distribution of power-law fluid under fluctuating