In Order to solve Me problem that polymer gel is not suitable for profile control in high temperature and high salinity reservoirs. a good inorganic profile control agent (Na2O center dot mSiO(2)) is studied in this article. The results show that sodium silicate in high temperatures and high salinity can self-generate white precipitation, which can effectively block high permeability zones and/or thief zones and expand sweep volume. The precipitation mass is related to modulus, temperature,salinity, and aging time in high temperatures. Sand-packed models experiments indicate that sodium silicate in high temperatures and high salinity has a good blocking and oil displacement effect, which can further enhance ail recovery. Field application results. also confirm Mat sodium silicate is a good inorganic profile control agent in high temperature and high salinity reservoir.