<p>Preheating combustion/gasification technology enables efficient and environmentally friendly utilization of coal resources, but the research on the flow and reaction characteristics of high-temperature gas-solid mixed fuels produced by the technology still needs to be further explored. The flame can intuitively show the jet, mixing and reaction of fuel and oxidant at the outlet of the burner. Therefore, this study investigates the jet flame characteristics of high-temperature gas-solid mixed fuels on a self-designed test platform. High temperature and gas-solid mixing are the special features of the fuel in this study, which are different from other studies. Therefore, we first qualitatively compare the jet flame characteristics of high-temperature gas-solid mixed fuel with traditional fuel. The preliminary results indicate that high-temperature gas-solid mixed fuels exhibit higher reactivity and a faster reaction rate compared to pulverized coal. As a result, it shows different characteristics in flame shape, ignition delay and ignition mode. The jet flame shape of high-temperature gas-solid mixed fuels closely resembles that of the pulverized coal group combustion flame, displaying a continuous cloud-like structure similar to the shape of a gas-fueled flame. Furthermore, the flame image does not show any significant ignition delay phenomenon. Building upon these results, this study also quantitatively analyzes the geometric parameters, temperature distribution and oscillation frequency of the high-temperature gas-solid mixed fuel jet flame under different secondary air equivalence ratios and primary air equivalence ratios, so that we can have a deeper understanding of the influence of operating parameters on the combustion/gasification process.</p>