Abstract: Opposing jet technique as an active flow control method has the potential to realize efficient drag and heat reduction for high-speed vehicles. In order to investigate the drag and heat reduction mechanism of the opposing jet in different typical flow modes, the surface pressure coefficient and adiabatic cooling efficiency at different jet stagnation pressure ratios (PsR = 0～6.0) under the incoming flow of Ma = 10 are numerically calculated for a blunt body featuring an opposing jet orifice. The results show that with the increase of jet stagnation pressure ratio PsR, the opposing jet will experience three typical flow modes, namely, unsteady short penetration mode, unsteady long penetration mode and steady short penetration mode. The unsteady short penetration mode does not achieve efficient heat and drag reduction and should be avoided. The unsteady long penetration mode offers high drag reduction performance at low PsR values due to the reduction of the interface cone apex angle brought by the longer bow shock stand-off distance, however, its heat reduction effectiveness is compromised due to increased mainstream aero-heating from the sharpened interface structure and reduced opposing jet total enthalpy. In the steady short penetration mode, increasing PsR improves drag reduction by decreasing the interface cone apex angle and increasing the bow shock stand-off distance, and the heat reduction effect is improved by the decrease of the mainstream aero-heating at the interface and the increase of the opposing jet total enthalpy. It can be seen that although long penetration mode and short penetration mode show different drag and heat reduction characteristics, their intrinsic physical mechanisms of drag and heat reduction are the same. The steady short penetration mode is more suitable for addressing the challenges of high aerodynamic drag and heating in hypersonic flight.