The invention provides a profile controlling and displacement system. The system is prepared from, by weight, 1%-3% of nanometer titanium dioxide, 0.2%-0.9% of cetyl trimethyl ammonium bromide, 0.01%-0.3% of partially-hydrolyzed polyacrylamide and the balance water. The invention further provides a preparation method and application of the profile controlling and displacement system and a displacement method which adopts the profile controlling and displacement system and is used for oil reservoirs for reservoir oil. The profile controlling and displacement system is suitable for complex oil reservoirs with harsh conditions, has the advantages of temperature resistance and salt resistance and can achieve the excellent effect of displacement of the reservoir oils.