Taking a deep-buried underground petroleum storage caverns as the research object, the effect of different grouting parameters on the penetration distance of slurry were studied for fractured rock mass by using discrete element method and UDEC software, and setting the slurry to be a Bingham fluid model. Research results showed that: increasing the grouting pressure can increase the penetration distance of the slurry, but at the stage of high filling pressure, more grouting pressure was used to overcome the deformation of the surrounding rock； the larger the fracture density, the larger penetration distance of the slurry, but the changes was small. The penetration distance of the slurry increased with the increase of the crack width, and finally tended to be stable. The penetration distance of the slurry decreased with the increase of the slurry viscosity and tended to be stable.