In order to obtain better sealing effect，a kind of epoxy resin with special hydrophilic group was prepared in the laboratory，and the resin system was prepared by mixing the epoxy resin with the corresponding curing agent. The physical properties such as curing temperature and thermal stability of the resin system were analyzed，the effect of the resin system on the sealing ability of cement slurry was studied，and the microstructure of resin cement slurry was studied by scanning electron microscope and energy spectrum analyzer. The results showed that the curing effect of the epoxy resin mixed with the corresponding curing agent was good. The curing temperature was between 39.9℃ and 164.6℃，and the thermal stability of the cured product was good below 243.9℃. When the resin system was added into the oil well cement slurry，the sealing capacity of the cement paste could be significantly improved. Compared with the blank cement slurry，the permeability of cement paste formed by the cement slurry with 15% resin decreased from 0.037×10-3 μm2 to 0.023×10-3 μm2，decreasing by 37.8%；the cementation strength increased by 77.8% from 1.8 MPa to 3.2 MPa；the elastic modulus decreased from 9.86 GPa to 4.08 GPa，decreasing by 58.6% . The microstructure of cement paste showed that after the resin and cement slurry were solidified，the solidified products and hydration products of the resin was mixed to form a whole，and the unreacted resin polymer particles were filled in the cement paste to form a flexible structure center. The two functions jointly improve the sealing ability of cement slurry.