Abstract: In order to study the detonation mechanism problems in the elevated initial temperature supersonic flow,a continuous heater was designed and employed to produce supersonic premixed hydrogen/air mixture flow,with Mach number of 2.6 and static temperature above 700 K;and the high speed schlieren was used to observe and analyze the direct initiation and development process of the detonation.The result shows that the oblique shock angle before the detonation initiation and the detached detonation angle are consistent with theoretical analysis.It is also found that the transition from the deflagration to detonation induced by oblique shock is rapid,and the phenomenon of detonation failure and re-initiation will exit under the circumstances of high initial temperature and low stoichiometric ratio of combustible mixture.The results obtained here provide a reference for the application of detonation in the hypersonic propulsion.