There is no surface water injection process in the high-temperature and high-salt self-source water injection reservoirs in the east of South China Sea. The conventional profile control and flooding agent can’t be directly injected into the reservoir after mixing on the ground. It is difficult to inject into the reservoir because the conventional profile control and flooding agent has poor self-dispersion. Focusing on the A oilfield in the east of South China Sea，the self-dispersed profile control and flooding agent with high temperature and salt resistance was developed by gelation reaction and mechanical grinding miller. It was composed of polyphenol crosslinking agent，multi-branched chain alcohol polyether dispersant，and temperature-resistant and salt-resistant polymer with a content of 40% AMPS. The particle size，micro-morphology and surface electrical properties of the profile control and flooding agent were studied by laser particle size analyzer，electron microscope and dynamic light scatterer. The self-dispersion performance，injection performance and profile adjustment performance were evaluated. Finally，the field application was carried out in the X well Group of A oilfield in the east of South China Sea. The results showed that the self-dispersed profile control and flooding agent was spherical. The D₅₀ of initial particle size was 1.09—11.63 μm. It could be adjusted by changing the formula， grinding conditions or heating time. The surface of this agent was negatively charged. The Zeta potential value was -19.30—-26.1 mV. Compared with the conventional oil dispersing granule agent，the self-dispersing performance of this agent was good. It could be quickly and evenly dispersed after entering water while the self-dispersed rate in injected water was 90.0%. Furthermore，the core injection pressure was only 53.13% of that of oil dispersing granule agent. After chemical treatment，the flow ratio of high permeability core decreased from 92.6% to 20.5%，while that of low permeability core increased from 7.4% to 79.5%. The water absorption profile was obviously reversed. The field test effect was good. The increasing pressure after injecting the profile control and flooding agent was 0.5 MPa. The maximum daily oil increase was 106 m³ after field test，and then the stage increasing oil was 8900 m³. The profile control and flooding agent met the high temperature and high salt condition of target oilfield. It had good injection performance and obvious increasing oil effect，which was suitable for the self-source water injection reservoir.