Air has the characteristics of low-temperature oxidation (LTO) as well as improving drainage energy. Therefore, it can be co-injected with steam to enhance an oil recovery factor. This paper studies combined steam air flooding for heavy oil recovery. Four experiments, including one steam flooding experiment and three combined steam-air flooding experiments, are studied. The volume ratios of air and steam in these three combined flooding experiments are 1:2, 1:1, and 2:1, respectively. The experimental results show that combined steam air flooding can enhance the oil recovery factor when the volume ratio of air and steam is in a certain range. Furthermore, numerical simulation results show that its temperature and oil recovery tendency are similar to those from the experiments. In the numerical simulation study, an optimal volume ratio of air and steam is 1.5:2. Finally, a field test of combined steam air flooding in the Qi-40 block of the Liaohe oil field is studied to validate the experimental and numerical results. Results show that air can be an effective additive that enhances heavy oil recovery in a steam flooding process.