According to the characteristics of high water cut, serious water channeling and poor water drive development in a block of Daqing Oilfield, a new polymer composite nano⁃microsphere profile control and oil displacement agent NWQ⁃2 was developed by dispersion polymerization method, and its particle size distribution, water absorption and expansion performance, temperature and salt resistance performance, viscoelastic performance, profile control and plugging performance and oil displacement performance were evaluated in the laboratory. The results show that the average particle size of NWQ⁃2 is 512.6 nm, and the particle size distribution is uniform. The water absorption expansion ratio in distilled water for 20 h can be more than 10 times, and that in high temperature (120 ℃) and high salinity water (75 200 mg/L) for 20 h can still be more than 8 times, which shows that NWQ⁃2 has good water absorption expansion performance,temperature resistance and salt resistance. After water absorption and expansion, it has good viscoelasticity, good profile control and plugging effect for cores with different permeability, which can effectively block large channels, increase injection pressure, and make the subsequent injected fluid enter more micro channels. After injection of 0.5 PV composite nano microsphere NWQ⁃2 into heterogeneous core, the recovery of core after water flooding can be significantly increased by more than 20%, which has good oil displacement effect.