Abstract: In order to extend the steady working flow range of micro can combustor, an adjusting device has been proposed. By means of CFD software package, the numerical simulation of the flow field without reaction in micro can combustor was implemented, and impacts of geometric parameters on flow field were determined. The simulation result gives the detail guide to complete the technical design of the micro can combustor. Further, simulation also show that the proposed adjusting device can change the flow field, and may provides proper flow condition with different flow rate for steady combustion. Experimental investigation proves the effectiveness of the adjusting device, which can expand the steady combustion flow range of a micro can combustor.