Euler equations with chemical reaction were used to study the difference in the initiation mechanism and characteristics of saltation and smoothness oblique detonation waves (ODW).The result shows that the criterion which determines the oblique detonation wave configuration is whether a subsonic zone exists behind the oblique shock wave(OSW).If the OSW raised by the flame behind it can lead to the formation of a subsonic zone

the transverse shock wave and triple point would appear and saltation ODW would form.The smoothness ODW would form if all zones are supersonic behind the OSW so the flame can not touch the upriver OSW.The OSW critical angle which leads to the formation of transverse shock wave is calculated from the equations of OSW.When the OSW angle is bigger than this critical angle

saltation ODW would form.otherwise

smoothness ODW would form.