Abstract: Opposing jet flow control technology has a broad application prospect and can achieve effective drag reduction control under long penetration mode (LPM). In order to further study the opposing jet mode conversion mechanism and the influence of incoming flow conditions on drag reduction control of hypersonic vehicles and related mechanisms, wind tunnel tests were conducted on the blunt body model under different incoming total pressures (0.1MPa, 0.4MPa), Mach numbers (Ma5, Ma6) and jet total pressure ratios. The structure of the spatial flow field and the surface pressure distribution of the model were obtained by using high-speed Schlieren and electronic pressure scanning valve. The results show that the LPM flow is extremely unstable, with strong unsteadiness and asymmetry, and the flow field presents axial and radial oscillations. At the transition phase, the flow field oscillates axially and changes continuously between LPM and short penetration mode (SPM). SPM flow is stable and the flow field structure is axisymmetric. As the total pressure ratio increases, the surface pressure distribution of the model corresponds to the phase of jet mode transition. The critical total pressure ratio of the jet is affected by the total incoming pressure and Mach number. As the total incoming pressure increases, the critical total pressure ratio increases, and the total pressure ratio interval corresponding to LPM becomes larger. With the increase of incoming Mach number, the minimum total pressure ratio and critical total pressure ratio of sonic jets decreases, and the total pressure ratio interval corresponding to LPM becomes smaller.