The invention discloses a preparation method for a polymer with a penetration network structure and used for a grouting material. The preparation method comprises the following steps: (1) subjecting diisocyanate and vegetable oil based polyol to a contact reaction so as to obtain a vegetable oil based polyurethane prepolymer; and (2) adding hydrogenated silicon nitrile rubber particles, epoxy resin, a curing agent, a diluent and a curing adjusting additive into the vegetable oil based polyurethane prepolymer obtained in the step (1), carrying out uniform mixing in an inert atmosphere environment, and carrying out vacuum degassing and curing so as to obtain a vegetable oil based polyurethane/epoxy resin polymer with the penetration network structure. The method provided by the invention reinforces the vegetable oil based polyurethane, toughens the epoxy resin, improves the physical and chemical properties of the polymer with the penetration network structure, and is specifically applicable to application in grouting and leaking stoppage in a complicated geological-condition structure.