Abstract: Experimental studies on the combustion and flow process in a scramjet combustor with strut fuel injector were presented.The results show that,the relative position of the fuel injector(strut) and flame holder(cavity) has great influence on the flame structure and scramjet performance.The combustion efficiency of fuel injected from the side of strut is better than from strut end.Combustion and flow process interact with each other intensively.Due to the quantity of heat released from combustion,the flow structure changes greatly,consequently,the fuel injection,diffusion and mixing with air are affected.