Abstract: Under complex incoming flow conditions over a wide speed range, shock/boundary layer interference and the real gas effect at high Mach numbers jointly cause the inlet to fail to start, severely restricting the stable operation of the engine. Therefore, it is urgent to conduct research on the flow field characteristics and flow control technologies of the inlet under the background of wide speed range. The flow field characteristics of wide-speed-range inlets were systematically summarized. The influences of real gas effect on boundary layer transition and flow separation were highlighted. The effects of angle of attack, back pressure, freestream Mach number and sideslip angle on the starting performance of inlets were summarized. The control mechanism and performance advantages of variable geometry inlets, synthetic jets and their derivatives were sorted out. The future research should focus on the flow mechanism under high enthalpy real gas effects, combined flow control and adaptive intelligent flow control, to provide theoretical references for the stable operation of the inlet under all operating conditions in the wide speed range.