The core-shell polymer microspheres PMS@SiO2 were prepared by dry water method using hydrophobic SiO2 and aqueous phase containing monomer, initiator ,crosslinking agent and water. The effects of SiO2 hydrophobicity, the ratio of silicon and water, stirring speed and stirring time on the formation of stable dry water microreactor were investigated. The polymerization conditions of core water phase were optimized by orthogonal experiment, in which ammonium persulfate and sodium bisulfite were used as initiators ,N,N'-methylene bisacrylamide was served as a crosslinking agent. The chemical structure, thermal stability and microscopic appearance of the microspheres were respectively characterized by Fourier transform infrared spectroscopy(FTIR), thermogravimetric analyzer(TGA), laser particle size analyzer, scanning electron microscope (SEM) and transmission electron microscope(TEM), its water swelling and flooding performance were also evaluated. The results showed that the best preparation condition of core-shell polymer microspheres PMS@SiO2 were as follows: the mass ratio of SiO2-R812S and water phase was 1:10, the stirring speed and stirring time were respectively 12,000 r/min and 120 s, the amount of crosslinking agent and initiators were respectively 0.1% and 0.15%, the reaction temperature was 50 ℃ and the reaction time was 4 h. The microspheres were hydrated at 90 ℃ for 20 days, and its expansion times was about 5.0. Compared with the conventional polymer microspheres PMS, PMS@SiO2 showed slower expansion. The results of physical model displacement experiment indicated that the plugging ratio of PMS@SiO2 could reach 90.39%, the residual resistance coefficient was 10.409, and the recovery rate can be increased by 34.02%. The recovery rate of PMS@SiO2 was 11.89% higher than that of PMS, with good profile control and displacement performance.