In heavy oil thermal recovery processes, higher pressure usually leads to low dryness and expansion difficulty for the injected steam in thermal recovery processes, which will result in lower oil recovery and more carbon emissions. This paper proposed a new CO₂-inducing method to accelerate the steam chamber expansion, based on a core flooding experiment and numerical simulation. First, the CO₂ showed significant viscosity reduction at high pressure in the PVT test. In the core flooding experiment, the CO₂ provided strong flow conductivity in porous media for the thermal flooding, as the CO₂ pre-injection restrained the steam condensation. Using the CO₂-inducing method, CO₂ pre-injection before steam built a fast flow channel in a relatively higher permeability layer and reduced the thermal injection pressure by about 1.0~2.4 MPa. As a result, the steam overlap around the injection wells became slower and the gravity drainage process was able to heat and displace the heavy oil above the channel. Furthermore, the CO₂ gas trapped at the top reduced heat loss by about 12.4%. The field numerical simulation showed that this new method improved thermal recovery by 7.5% and reduced CO₂ emissions by about 18 million kg/unit for the whole process. This method changes the conventional thermal expansion direction by CO₂ inducing effect and fundamentally reduces heat loss, which provides significant advantages in low-carbon EOR.