© 2017 Published under licence by IOP Publishing Ltd. An experimental research has been conducted to investigate the flow control method using opposing jet with air and water as a fluid spike on a bunt body in hypersonic freestream at Mach number 7, using the Kashiwa hypersonic wind tunnel. The dynamic characteristics and instability of opposing jet were clarified. It can be seen from the comparison between the air opposing jet and the water opposing jet that a liquid jet seems more effective in generating fluid spike for reduction in the drag force and the heating rate on the body. Details of the flow field and the jet oscillation have been captured by Schlieren system with high-speed cameras. The experimental data reveal the interaction of the jet oscillation with the shock wave fluctuation. Such interaction has strong impact on the whole flow field structure and should be taken into consideration in the design of the active flow control system using the opposing jet method.