Through the utilization of contact experiments between the CO2, crude oil and brine, Fourier-transform infrared spectroscopy testing, component analysis of crude oil, and microfluidic technology, this study investigates the role and mechanism of CO2 on the formation of micro-dispersion in the crude oil-low salinity water system. It reveals the microscopic mechanism of the micro-dispersion effect in low-salinity water-CO2 alternating flooding and clarifies the polar chemical bonds and their source components responsible for micro-dispersion. According to the research, the main factor for micro-dispersion formation is the interaction between the polar bonds of C=O and C-H in crude oil and O-H polar bonds in water. The number of micro-dispersions at the CO2- brine -crude oil system interface rises monotonically as the salinity of the brine lowers. When light components are extracted from oil using CO2, the polar compounds that are encased in these light components separate and multiply, which promotes the formation of micro-dispersions. Higher hydrophilicity of the interface and a bigger reduction in viscosity of saturated CO2 in crude oil are the outcomes of the micro-dispersion effect. By diffusing into the oil phase, polar reverse micelles in low salinity water are able to capture dissolved water, increasing the number of adsorption interfaces for polar compounds, raising the chemical potential of CO2 + oil phase at the interface, and decreasing the difference in chemical potential between the interfaces of the CO2- brine -crude oil system.