The present invention provides a mixed injection fluid and a corresponding method for enhancing CO2 sequestration and oil recovery, which is a method of the geothermal driven CO2 catalytic reduction for enhancing CO2 sequestration and oil recovery. In the present invention, a technical solution of the liquid nitrogen fracturing, an injection fluid injection, and the catalysis transportation and storage were adopted, which makes full use of the thermal energy of deep geothermal reservoir in combination with nano-Cu-based catalysts to activate the hydrothermal cracking reaction of crude oil and CO2 thermal reduction reaction, so to simultaneously enhance crude oil recovery and CO2 sequestration, fundamentally solving the existing problems of CO2-EOR technologies. Moreover, CO2 thermal catalytic reduction products can also work as a surfactant to accelerate the desorption crude oil from the rock surface and decrease the interfacial tension, and finally EOR.