Abstract: The development of heavy oil reservoirs primarily relies on steam injection-based thermal recovery techniques, which directly produce over 1.2 tons of carbon emissions per ton of oil and face challenges such as insufficient downhole steam quality in deep reservoirs. To achieve low-carbon and efficient extraction of heavy oil, an unconventional downhole electric heating technology was developed to enhance steam quality. This technology was equipped with a sealing system and power regulation device, enabling efficient conversion of electrical energy into thermal energy to improve downhole steam quality. Based on the structure of steam injection wells, the calculation model for steam injection parameters of electrically heated wellbore was derived to predict downhole steam pressure and quality. Field tests demonstrate that the downhole electric heating technology can increase the steam quality injected into the well at a rate of 7.0 t/h by 11%. The production cycle of the test well shows a significant increase in oil production, with a maximum daily increase of 5.0 t/d and a cumulative incremental production of 353.1 t during the test period, indicating notable enhanced oil recovery. Due to the wide availability of green electricity sources, this technology has provided technical support for the low-carbon and efficient development of deep heavy oil reservoirs.